FRIDAY, SEPTEMBER 9, 1887.

IN A COMMUNICATION made last year to the French Academy of Medicine (Science, viii. p. 29), Dr. Worms gave the results of his investigations concerning color-blindness among the personnel of the Northern Railway. The figures which he gave showed so small a percentage of color-blind employees as to warrant the conclusion that there is not much danger to be feared for railroad travellers from these defects. More recently Dr. Worms has informed Dr. Jeffries of Boston that this percentage was found among those employed after all had been examined on entering the service previously, an explanation which gives an entirely different phase to the matter. The statistics given by Dr. Worms, and to which we have already referred, have been repeatedly quoted as an argument by those who do not admit the prevalence of color-blindness among railroad employees, and who therefore deem color-testing unnecessary. This use of the figures of Dr. Worms, which was justifiable in view of the form in which they were originally given, should now be abandoned in view of the later information received from him. This subject of color-blindness among railroad employees is attracting the attention of thoughtful men in all parts of the world. In our own country, Massachusetts has a statute in relation to the matter. This directs that no person shall be employed upon a railroad in any capacity which requires him to distinguish form or color signals unless he has been examined as to his sight by some competent person employed and paid by the railroad company, and has received a certificate. The phrase 'competent person' is a very elastic one, and it is feared that the examiner is not in all cases competent to make the tests. The Alabama legislature has enacted a law which is pronounced to be the best yet devised to overcome this evil. It provides for examinations conducted by experts, not according to rules of their own, but guided by standards both of visual power and of color-sense which are fixed by law. The railroad employees, under this law, are divided into two groups,

one containing engineers, firemen, and brakemen, in whom a high visual power and color-sense are demanded, and the other containing gatemen, conductors, and others, to whom an inferior standard is applied. Connecticut at one time had a law upon this subject, but, after one year's trial, so many employees were found deficient that in obedience to the demand of politicians it was repealed. In one instance a board of experts found twenty-four railroad employees to be color-blind. Their report of these facts created such an outcry among their friends that another test was demanded, with flags and lanterns and not with colored worsted as in the former test. This resulted in proving that of the twentyfour, twenty-one were wholly color-blind, and three color-blind in part. Dr. Worms has recommended that exercises on the colors should be carried out in the schools to reduce the percentage of the color-blind. In commenting on this recommendation, Dr. Jeffries says that no exercise with colors can change the congenital color-blind, who are four per cent of males everywhere. We hope to see this subject agitated until the provisions which are now in force in Alabama shall apply throughout the United States. It matters little to a traveller that his life is secure in one State by reason of stringent laws against color-blindness in railroad employees, if as soon as he crosses the boundary line and passes into another State, in which no such law exists, his life may be sacrificed by a colorblind engineer who, mistaking the red light of danger for the white light of safety, runs his train through an open drawbridge into the river below.

CO-OPERATION ON THE CONTINENT OF EUROPE. II. GERMANY.

THE reply from Germany to Lord Rosebery's circular letter (see Science, No. 220, p. 395) is more systematic than that from France. At the very outset the writer says that among the working-classes of Germany co-operation has met with little favor: the well-to-do classes, on the other hand, have applied its principles with considerable success in many directions. This reluctance on the part of the working-people to co-operate is ascribed in a large measure to the fact that as a class they are incapable of appreciating the value of making provision for the future. They are not yet educated up to the point of making industrial co-operation a real factor in the improvement of their condition. The tendency toward State socialism in Germany is also an obstacle to co-operative development. Statistics as to co-operation are not easily obtained in Germany. Both the government and private societies are very reticent when asked for information on commercial or industrial questions. The most observant notice of co-operative movements, so far as they concern the artisan and laboring-classes, is probably taken by the Central Association for the Welfare of the Laboring-Classes, and its organ, the Arbeiterfreund; while very valuable statistics are to be found in the yearly report of the Central Union of German Co-operative Societies, on all which the report from Germany is based.

Associations belonging to this Central Union of German Cooperative Societies are entitled 'Registered Associations,' and are established under the Prussian law of March 27, 1867, and the German law of July 9, 1868. These laws grant special privileges to co-operative societies; that is to say, associations not restricting themselves to any fixed number of the members composing them, and got up with a view of facilitating the obtaining of credit, the earning of a livelihood, or prosecution of husbandry by their members by means of joint management of their business. A great number of associations have united themselves under the leadership of a counsellor in the Central Union.

Such enterprises are in Germany indissolubly connected with the name of their great founder, Schulze-Delitzsch. The movement, which he started and organized with extraordinary genius, is entirely based on the principle of self-help.'" If a man cannot save a few pence by denying himself a couple of glasses of beer a week," said Schulze, "I can do nothing for him." The history of Schulze's attempts are briefly as follows: In 1849 he founded at Delitzsch, in Saxony, a sickness and death' fund, which, for a small monthly subscription, afforded help and medicine to the poorer artisans and laborers in case of illness, continuous pecuniary support in cases of incapacitation for work, and contribution towards funeral expenses in cases of death. In 1850 Schulze started a loan society, and, in re-organizing the same in 1851, he introduced the principle of unlimited liability, and completed his system, as far as essentials were concerned, by forming capital for individual members by the introduction of inalienable shares. The example thus set was quickly followed, and many mutual help societies sprang up in various parts of Germany.

The principle of unlimited liability, on which Schulze most strongly insisted as the keystone of his system, was also adopted by Raiffeisen, who founded similar societies, chiefly in agricultural districts. The double effect seems to have been to raise the credit of co-operative societies, and to confine them to persons of small means, persons of larger fortune being shy of risking their whole property.

As mentioned above, the societies on the Schulze-Delitzsch plan have been regularly organized into an association, the principal objects of which were briefly described by him in the report of 1874 as being the following: "The General Union of the German Industrial and Economical Co-operative Societies, founded on the principle of self-help, the affairs of which are at present managed

by me as a salaried agent, sends delegates of the associations belonging to it to an annual general assembly, which controls the affairs of the union as supreme authority, without interfering with the independence or with the special affairs of the individual societies. As connecting links between the central authority and individual associations, subordinate unions, which embrace the societies of various German countries or provinces, or of special branches, have been formed, whose task it is to attend to their special interest, and to communicate between them and the central authority. They prepare for the general assembly in special assemblies of their own, and enforce the resolutions of the former in their districts, while the presidents chosen by them form a committee which assists the agent in carrying on the business of the union in the interval between the general assemblies. Thus, without interfering with the free action of the individual societies, a central point is created for the exchange of experiences, for the sifting and criticising of the ever-accumulating material, for advice and help for members in any kind of embarrassment, and finally for common defence against threatening danger. Add to these advantages the most valuable business relations between the several societies in the execution of commissions, and especially in mutual assistance with capital." The resolutions of the general assembly have only the force of advice, and their acceptance is enforced only by the weight of their own reasons, and not by pressure of any kind.

The number of societies in this association increased from 171 in 1859, to 771 in 1864, and was 3,822 in 1885. At the last-named date they were distributed thus: loan and credit societies, 1,965; co-operative societies in various branches of trade, 1,146; co-operative store societies, 678: building societies, 33. At the end of 1884 the membership was 1,500,000. Of their own capital, in shares and reserve funds, they possessed 300,000,000 marks; and of borrowed capital, 500,000,000 marks.

It may be mentioned that the co-operative movement in Germany is unfortunately at present associated with the Radical political opinions. Even Schulze, though at first he kept the movement free from political color, was carried along by the tide in his later years. The consequence has been that co-operative enterprise on the self-help principle is looked upon rather with suspicion by the ruling authorities.

Co-operative store associations exist in considerable numbers in Germany, and are in the main very successful. They bear the name of Consumvereine. Many of the earlier associations confined themselves to making contracts with dealers, provided that the latter granted a discount to the association on all goods sold, which discount was, after deduction of expenses, divided among the members.

Those formed since 1863 have followed more and more the principle of similar English associations. They give no credit, sell at the market price, and, after providing suitable interest for the business shares of the members, divide the net profits in proportion to the goods bought, which proportion is marked by dividend counters; but there are some very well conducted societies which sell at the lowest price possible, and divide the profits equally, or in proportion to the business shares of the members. As in England, the more developed societies are gradually undertaking the production of their own goods. The South German associations have taken a step towards the establishment of a common wholesale business by forming a joint stock company for the purchase of goods at Mannheim in North Germany this was in 1878 still regarded as premature. Nearly all the important co-operative store associations have registered themselves under the Co-operative Societies' Law.

The proper principles on which such associations should be conducted are laid down by Schulze-Delitzsch as follows: 1. Those who buy from the society should themselves be members of it (sale to non-members is, however, allowed as being likely to induce the latter to join); 2. Business shares should be gradually acquired by the members up to a normal sum by the payment of a small subscription, or by accumulation of their dividends; 3. A common reserve fund is formed by keeping back a certain number of shares, and by a small entrance fee for members; 4. Capital is borrowed on the common security of members, or (though this should be avoided) goods are bought on their com

mon credit; 5. Sales are for ready money, the profits being divided between the reserve fund and the members' dividends; 6. The manager and officials are paid according to the work they do; 7. The number of members is unlimited, entry into and withdrawal from the society being equally free.

These rules, being stamped with the great authority of Schulze, represent the general principles on which the vast majority of cooperative associations work, and are recommended to all by the Central Union.

The number of these co-operative stores twenty-five years ago was 41; in 1885 it was 678. Their average sales in 1884 were 190,025 marks. Their average holdings in business shares are 24 marks 6 pfennigs per member, and in reserve funds 14 marks 3 pfennigs per member. One hundred and sixty-three of the societies showed, in 1884, a dividend on capital and purchases of 2,412,366 marks, or 85 per cent.

For the failures in 1884 numerous reasons are given. One society failed in consequence of their "unfortunate choice of a storekeeper;" another in consequence of quarrels among the members; a third society were obliged three times to change their storekeeper, and eventually came to an end in consequence of the impossibility of finding a suitable person; a fourth came to grief in consequence of the desire of the members to divide the reserve fund. On this latter rock many societies have split. As soon as the society finds itself possessed of any considerable sum of money, individual confidence seems to give way, and greed of the immediate possession of their own share prompts the members to dissolve the association.

Co-operative workshops are not numerous in Germany, and the general opinion is unfavorable to them.

The favorable years, from 1870 to 1873, seemed to bid well for the establishment of a system by which the workmen should be made participators in the profits of their industry; and the governments of Germany took pains not only to try the system in their own works, but to obtain information as to its working elsewhere. The initiative was taken by Bavaria; and from an inquiry made in 1874 from fifty Bavarian firms, of whom about thirty sent replies, it appeared that in most cases such participation was contined to premiums, gifts, and a percentage to overseers and foremen. These cases were chiefly the result of individual liberality on the part of employers of labor, and, as they ceased in the time of industrial depression which succeeded, they are without scientific value.

The 'Report on Arrangements for the Benefit of Workmen in the Larger Industrial Establishments of Prussia,' published in 1876 by the Prussian Government, states that at that time there were 439 cases of establishments in which the workmen shared in the profits, and 61 where they shared in the capital. A closer analysis of these figures, however, shows that in most cases such participation was confined to the foremen and overseers, and that in only 16 cases did all the workmen have a share at once in the undertaking, and in 18 others after a certain lapse of time.

Schulze-Delitzsch always declared that productive associations, i.e., “associations of a number of small masters or of wage-laborers for the purpose of industry on a large scale for common account and at common risk," was the highest form of association, and the keystone of his whole system. Such associations, he pointed out, are most easily established the less capital they require, and the more readily the goods produced are sold. They are most difficult to establish in branches of industry which, owing to minute division of labor, require the co-operation of workmen of different trades, or which entail expensive machinery.

Hitherto the general history of productive associations in Germany seems to have been pretty nearly the following: a not very large number of workmen join together to establish a common workshop and sell their products for common account. The original intention of admitting new working members is frustrated by the fact, that, whereas an individual capitalist can increase or diminish the number of his hands according to the requirements of the market, every unfavorable conjuncture has the effect, in a cooperative association, of leaving some of the members not fully occupied. When better times come, the admission of new members is looked on with disfavor, because it only renders the position of the others worse if times of depression return. There is, further,

the difficulty that the advantages shared by the new members are the result of sacrifices on the part of the old, for which the latter are not indemnified. It consequently results that the associations refuse to admit new members, and in good times employ regular workmen hired for wages and liable to dismissal, and thus in the moment of success such associations lose the essential characteristics of co-operative societies.

To meet these difficulties Schulze recommends:

1. The admission not only of members of the trade, but, as sleeping partners, of persons who, without taking any share in the industry of the association, are yet willing to venture a deposit of capital; and of workmen who enter the association at once, but, as they cannot be employed at once, remain for the time being as wage-laborers under other employers.

2. The participation of new members in the profits only after a certain lapse of time.

3. The application of borrowed capital, and not of the society's shares, to the acquirement of such real property as is required; such borrowed capital not being reclaimable before a certain date, but receiving interest.

4. Withdrawal from the association to be subject to as long notice as possible.

As to division of the profits, most German associations agree with Schulze, that, after the reserve fund has been duly considered, five per cent interest should be added to each business share; that then half the surplus should go to swell the shares as super-dividends, the other half being divided as bonus among all the workmen and officials according to the amount of salary they have received during the year.

It is very difficult to obtain accurate information respecting cooperative undertakings for productive purposes, as, from reasons of trade, such associations are very reticent with regard to their working.

In the report of the German Co-operative Union for 1884, 145 productive associations are mentioned under the following divisions:

21 Cabinet and instrument makers' associations.

The same report gives statistics of 10 associations which made a net profit of 5.5 per cent, allowing of a dividend of 13.6 per cent, as against 16.0 per cent in 1883, and 13.5 per cent in 1882. Whether this dividend is paid to the members in money down or not does not appear. Of the working capital of these societies, 36.4 per cent was their own.

Herr Borchet is the only authority who believes that the workmen's participation in the profits has prevented strikes.

The most conspicuous examples of co-operation in production are the Berlin Brass-Work Company, the Windhoff Foundry at Lingen, Möller's engine-works at Kupferhammer, Keilpflug's cigarfactory in Berlin, and the cotton-mills at Hasel.

Of all co-operative enterprises in Germany, the people's banks are the most developed and the most successful, and they appear to have in a great degree overcome the indebtedness and misery which were so often the lot of the working-classes a quarter of a century ago, in consequence of the usurious interest that they were compelled to pay, especially in agricultural districts, on even the smallest loan.

ors, and the loan-takers pay to the fund of the association bank, interest and commission, according to the rates in the moneymarket. The managers, especially those who have charge of the funds, receive remuneration according to their services.

3. By full payment once for all, or by small continuous contributions on the part of the members, shares in the capital of the association are formed, according to the amount of which the profit is divided, and placed to their credit till the full normal sum is reached, by which means an ever-growing capital of its own is acquired for the business of the association.

4. By the entrance fees of members and by reservation of shares, a common reserve fund is accumulated.

5. Sums further necessary for the complete carrying-on of the business are borrowed on the common credit and security of all the members.

6. The number of members is unlimited. Entrance is open to all who satisfy the requirements of the statutes, and it is free to any one to cease to be a member after giving due notice.

Not only artisans and manufacturers, but also others, especially agriculturists, merchants, and dependent workmen, avail themselves of these banks, and they have maintained and strengthened themselves in the confidence of the public through all crises.

The Giro-Union (Circulation Union') of German associations deserves special notice. An account is opened at the Associations' Bank in Berlin in favor of each people's bank belonging to the Union. Each bank keeps a deposit of at least 300 marks there, which can be increased by deposits in specie, by bills on Berlin or any Prussian bank, or places where there are other loan associations, or by the transferrence of the deposit of a third party from his account to their own it can, on the other hand, dispose of its deposit by transferrence to another account, kept by the bank, or by checks, bills payable at sight, or ordered consignment in specie. Though Schulze regarded this institution as extremely important, only a minority of the people's banks belonging to the general union belong to it also.

The number of people's banks belonging to the general union was 1,961 on Jan. 1, 1885.

Co-operative societies for educational purposes would appear not to exist in Germany, where educational facilities in every branch of learning are already amply provided for, and within the reach of the poor; but co-operative associations of various kinds often provide educational, social, and recreative facilities for their members.

Societies for building dwellings for the poorer classes have met with but little success in Germany. They appear to have succeeded best in Alsace; and one at Flensburg, in Jutland, founded in 1878, possesses, according to the report of 1884-85, 19 houses, with a value of 100,000 marks, and 800 members, one of whom has the sum of 87,000 marks to his credit in the society's books.

The formerly wide-spread system by which pasture-land, forest, fisheries, etc., were held in common, has almost entirely ceased to exist in Germany, in consequence of recent legislation. On the other hand, a movement has taken place, chiefly under the same auspices as the co-operative movement on the Schulze-Delitzsch principle, by which combination now plays a very important part in German agriculture.

Dairy co-operative associations have been started in all directions. There are further associations for the purchase and use of agricultural machines, the members paying a certain sum for the use of the common property, and associations for cattle-breeding, sheep-farming, hops, vegetable, and vine-insurance, and kindred objects.

THE STONE AGES IN TUNIS.

AN interesting report on the relics of prehistoric man in the regency of Tunis appeared in the May number of the well-known scientific periodical, the Matériaux pour l'Histoire Primitive et

1. The loan-seekers are themselves the directors of the institution established for the satisfaction of their needs, and share the risk and the profit.

2. The transactions of the association are based throughout on business principles: the fund of the association pays to the credit

the Anthropological Society of Paris for this purpose, spent three years in traversing the country in every direction, and in making the observations and collections which are described in this report. Only the principal results can here be noticed; but these, it will be seen, are of great scientific value.

The most important observations were made in the district about

Gafsa, a considerable town in the southern part of the regency, preserving the site and the name of the Roman Capsa. The author describes three remarkable hills, which rise to a moderate elevation in the neighborhood of that town. These hills, having been made posts of observation of the occupying army, are now known as Posts I., II., and III. Post I. is an eminence rising on one side, by a gradual slope, to a height of sixty metres (about two hundred feet) above the level of the town, and descending on the other side in a steep, cliff-like face, of forty-two metres, to an upland plain. This precipitous face offered to the investigator the advantages of a cutting, showing the composition of the hill from base to summit. It proved to be, in the greater part, a limestone conglomerate, in which are embedded small particles of quartz, with rolled flintstones of various sizes, and fragments of brown silex. Geologically, the hill belongs to the earliest period of the quaternary or pleistocene epoch. The lower half is of stone sufficiently compact to be quarried for building-stone. Above this is a layer, about eighty feet thick, of somewhat looser and more friable conglomerate, with larger embedded stones. And this, again, is surmounted by a stratum of yellow travertine, about six metres (twenty feet) thick, containing no flints.

The remarkable fact is, that throughout the conglomerate were discovered relics of human handiwork, in the shape of wrought flints embedded in the rock. Still more remarkable is the fact that in the lower and harder stratum these relics were all of one sort, while in the upper and looser layer that sort had disappeared, and other kinds had taken its place. In the lower stratum he found specimens of that rude tool the rudest of all tools - which is described sometimes as the drift-implement,' sometimes as the 'axe of St. Acheul,' and by Prof. G. de Mortillet, in his noted work La Préhistorique,' as the 'fist' (coup de poing), - a stone clipped into an ovoid or almond-like shape, and intended evidently to be grasped at the smaller end and used in pounding or hacking. With these were some of the coarse flakes, or clipped fragments, which usually accompany them. These stone fists and flakes were all in the typical forms which distinguish the work of the earliest quaternary race, variously known as the River-drift,' or 'Canstadt,' or 'Chellean' race, and were the only traces of human industry found in that

stratum.

In the looser stratum above, not one of the ovoid implements was found, though a single specimen was extracted just on the line of division between the two layers. All the worked flints in the upper layer belonged to what M. de Mortillet styles the Mousterian' type, but were mostly of a heavy, coarse, and worn appearance. They were of various shapes, - triangular points, thick blades, rude scrapers, and the like. Dr. Collignon is of opinion that the implements in the upper conglomerate stratum were a development of those in the lower; but the facts, as described by him, do not seem decisively to bear out this opinion. Finally, in the highest stratum of all, the travertine, as has been said, no flints of any kind were found. The hill known as Post III. resembles that of Post I., except that it is lower, and that the layer of travertine is wanting.

The necessary conclusions from these facts, as set forth by the author, are, that in the earlier part of the quaternary era this region was inhabited by the race or races of men who formed these implements. During a period of great but unknown length the land gradually sank, and was finally covered by the sea. When it again rose above the surface, the currents swept away nearly all the formation which had accumulated during this subsidence, leaving only a few hills, such as have been described, to indicate the original level. After this denudation, a new but briefer subsidence took place, giving rise to a new formation, and followed by a new elevation. These facts are shown by the evidences displayed in and around another hill, known as Post II. This is one of the foot-hills' of a small mountain-chain which sinks gradually into the plain at a little distance north of Gafsa. Around these hills and on their declivities are scattered many small mounds of clayey loam. These mounds rest on a layer containing many coarse Mousterian implements, exactly similar to those in the upper conglomerate of Post I. Above this layer is a stratum of argillaceous earth, between three and four metres thick, containing no flints. Then follows a thin layer or film of earth, about four inches thick, full of flint implements of every description. This layer clearly indicates what was for a considerable

period the inhabited surface. Above this layer are a few feet of earth; but the same implements are scattered profusely over the present surface, and are found below it where the soil is furrowed by the rains. They belong to every one of M. de Mortillet's 'ages,' subsequent to the Chellean and the earlier Mousterian; viz., the upper (or later) Mousterian, the Solutrean, the Magdalenian, and the Neolithic. So far as prehistoric Tunis is concerned, Dr. Collignon is satisfied that no distinction in point of time can be made among these different industries. It is clear, also, that they have continued in existence to a very recent period, since the soil which covers some of the Roman constructions holds flint implements of the same description.

A very curious fact, ascertained by Dr. Collignon, is that all these stone implements, of every age, are restricted to a comparatively narrow area in the south and west of Tunis. While they abound in that district, they are almost entirely absent from the northern and eastern portions of the country. Dr. Collignon does not attempt to explain this phenomenon. It may possibly be due to an early condition similar to that which exists at present in parts of our own continent, where two hostile races, like the Eskimo and the Athabascan Indians, are separated by a wide space of unoccupied land.

It should be mentioned that in the middle of the Tunisian territory there is a limited area, quite distinct from that in which the stone implements occur, where megalithic monuments - dolmens and covered passages abound. In one locality no less than four hundred dolmens were counted. These monuments Dr. Collignon believes to have been the comparatively late constructions of an intrusive tribe; and he is further of opinion that the descendants of this tribe and of the stone-implement makers still live in their respective districts, and are distinguishable by their very different physical traits. In the district of the dolmens the people are of rather low stature (1.63 metres, or about 5 feet 4 inches, an average which must be understood as including both sexes), with long heads (index 74), and a visage short, broad, and irregular, closely resembling in outline that indicated by the Cro-Magnon crania. On the other hand, the people of the south of Tunis are comparatively tall (1.69 metres, about 5 feet 6 1-2 inches), very dolichocephalic (index 73), with retreating forehead and chin, and projecting glabella and brows; the nose turned up, and the lips thick, but with no prognathism. They are neither negroid, Berber, nor Arab. In his view, they represent the earliest ethnic stratum of the existing population, and preserve the blood and the type of the people who dwelt in this region during the stone ages.

The positive conclusions which we seem authorized to draw from Dr. Collignon's report may be stated in a few words. They are, first, that the human race is of an immense antiquity, dating back to the beginning of the quaternary age; and, second, that the first race of men, judged from the relics of their industry, were of a very low grade of intelligence, little surpassing that of the most sagacious brutes; but how far this apparent defect of intellect was real, and how far it may have been due to the circumstance, that, as M. de Mortillet has suggested, the faculty of speech was yet undeveloped, is uncertain. Finally, it is plain that the period of this earliest stone age was of a vast duration, which can only be expressed in geological terms. The same may be said of the early Mousterian era, which perhaps formed part of the first age. As for the various so-called 'stone ages' which followed, it seems impossible to make any real distinction of periods among them. They all apparently form one modern epoch, not of very great duration, and not yet closed.

·

CHILLED ARMOR FOR LAND-DEFENCES.

THE Gruson Works of Buckau-Magdeburg have recently published a book of some size, written by Engineer von Schuetz, in which the system of construction of chilled cast-iron armor for use in the protection of earthworks and in the making of turrets for land-batteries, as devised by Dr. H. Gruson, some years ago, is described at length, and an account is given of the results of the experiments which have been made, from time to time, by several European governments, to determine its efficiency in resisting the impact of the heaviest modern ordnance. This work has been

translated into English by Commander Grenfell, R.N., and we are indebted to the courtesy of Captain Piorkowski, Dr. Gruson's representative in this country, for an early copy. The subject and the matter of the work are of exceedingly great importance to a nation which, as is the case with our own, is destitute of the most ordinary means of defence in the event of a foreign attack either by land or sea. So serious is our case, that, as remarked in a private letter from the Admiral of the Navy just received and lying under the hand of the writer, if we desire to learn what advances have occurred during the last twenty years, we must go to England, France, Germany, Russia, and even to Constantinople, to study those of the scientific and mechanical departments of the military and naval establishments, and not to our own army or navy. This work of Dr. Gruson would seem to illustrate such advances in the defence of coasts.

Dr. Gruson's armor is simply a chilled cast-iron shield, of which the body is a strong normal iron, while the surfaces on the exposed side are chilled like the tread' of an American car-wheel. Such enormous masses are handled, in this case, however, that correspondingly enormous chills are needed, and the manufacture of these plates becomes a matter of extraordinary difficulty and cost. All the resources of a great establishment are drawn upon, and all the ingenuity, knowledge, and experience of an able staff are called out in the prosecution of the work. Chilling, as is well known, probably, to most of our readers, consists in the casting of a peculiar quality of cast-iron, known as 'chilling iron,' in contact with a large mass of cold iron forming that part of the mould which is to form the surface to be chilled. The sudden abstraction of heat prevents the isolation of the carbon in graphitic form, as would otherwise occur in the slow process of cooling naturally, and insures its retention in the combined form, producing a steel layer of considerable depth. The depth so secured is dependent upon the quality of the iron and the efficiency of the chill,' as the iron mould is called. The latter must have great thickness and good conducting power to give best results in these applications. Successfully carried out, this process gives a surface harder than tempered steel over a strong and massive interior, the best possible combination, apparently, for an armor-plate.

Dr. Gruson constructs large fixed turrets and land batteries of such plates, and the results of trial indicate them to be more reliable defences than any wrought metal, whether iron or steel, or 'compounded,' yet introduced. The weight of these shields is too great for use in naval construction. The first trials were made in 1869, at the Tegel range, and it was found that all shots fired against the chilled plates broke into fragments, and that the plates bore the hammering with remarkable success. The experimental committee reported that the chilled armor was well adapted for its

use.

Later trials confirmed this opinion, and the Prussian government at once gave directions for its adoption in important lines of frontier defences, and Austria, Italy, and Holland followed its example. In all these trials the chilled iron shot were found superior, if well made, to any steel shot, except in one or two cases in which makers, like Krupp and the Ternitz company, had either succeeded in securing an exceptional quality of steel, or had found remarkably effective methods of tempering. Plates were tested of from 13.77 to 49.21 inches thickness, and were attacked by guns varying from 6 to 17 inches calibre, throwing shot weighing from 61 to 2,205 pounds. The thickness of plate was usually not far from three times the diameter of the bore of the gun to be resisted. The energy of impact was, in the case of the largest gun, over 47,000 foot-tons; which was only obtained, however, by firing at short range - 150 yards. In all such cases, the shield is subjected to more severe trial than would be likely to be met in actual battle. In trials last year at Spezia, with the 100-ton gun, the shot weighed a ton, and the powder charge 327 pounds, the velocity of impact being over 1,700 feet per second. The maximum penetration was four inches, the plates finally breaking up under repeated blows.

The method of proportioning is to give the plates a maximum thickness in inches equal to from one-fourth to one-third the fourthroot of the energy of the attacking shot measured in foot-tons. The total weight of each plate of which the armor is composed is not far from the weight of the gun expected to be used in the attack.

The system of defensive armor here described is one in which we have a peculiar interest. We have in the United States, in the Salisbury' and 'Hanging Rock,' and other brands, the best chilling irons in the world, and it would seem very possible that this may prove to be the best system for our purpose yet devised. It is especially one which we may hope to obtain permanent advantage from, as it seems probable that its advantages over other forms are not likely to be soon lost. R. H. THURSTON.

MENTAL SCIENCE.

Heredity of Mental Traits.

STATISTICAL inquiries have become a recognized instrument of research in mental phenomena. Mr. Francis Galton has set the pattern in his study of the life-histories of English scientists, in his investigation on the heredity of physical and other traits, in his record of development in childhood, in his researches on visual imagery; and his composite photography is simply a pictorial average.' Students of educational science have adopted the same plan: the contents of children's minds, the record of the daily progress of infants as affected by heredity and by environment, have been registered in almost every civilized country. The increased activity in this direction is sure to bear good fruit. As soon as modern psychology substituted, for the old notion of a single, uniform, typical mind innately endowed with definite faculties and ideas, and uniformly proceeding in definite grooves, the recognition of the endless diversity in every particular of human faculty, it was no longer sufficient to introspect one mind and record the results of your exploration as psychology: one must now use every possible method, study mind from all its many aspects, call in the aid of the psychologist, the pathologist, the educationalist, the anthropologist, and the sociologist, in order to present a picture that shall have the slightest chance of truly representing the reality. That such statistical researches are unusually open to various kinds of falsification, and are apt to be worked' for more than their worth, every one will admit. It requires great insight as well as caution and patience to draw from a series of answers on mental topics such conclusions as are really warranted without going beyond what the facts logically yield, and again without losing the suggestiveness of incomplete records. But all this is an argument, not against the use of such methods, but for the need of more such researches.

The French Society of Physiological Psychology—an organization constructed on a much more useful plan than our psychic research societies, and yet including such work as the latter dohave recently issued a circular of inquiry, similar to the Record of Family Faculty' of Mr. Galton. This blank they send only to persons of whose reliability, scientific zeal, and accurate observing powers they have abundant evidence. Each such person fills blanks describing a person with whom he is intimately acquainted, another for his friend's father, and a third for his mother. If he have sufficient knowledge of any other member of the family to answer two-thirds of the questions on the blank concerning him or her, he is to add such information. The person whose traits are described must be at least twenty-five years old, so that his character has fully matured. It goes without saying that the records will be treated in the most confidential manner.

The questions are grouped under six heads. I. Education and social position; II. Physical traits; III. Physiological traits; IV. Pathological traits; V. Moral traits; and VI. Intellectual traits. The first group asks for one's religion; his mode of education; his origin, whether of noble kind, wealthy or poor; and so on: it outlines the environment of the individual. Under the second group are questions regarding height; weight; size of head, whether small or large for the height; shape of forehead; color of hair and eyes, etc. The physiological questions test the sensibility of the several - of the eye as to near-sightedness, color-blindness, and the like; of the ear as to fineness; the development of taste and smell, and so on. They also include the temperament, i.e., nervous, melancholic, sanguine, and phlegmatic; the diet, whether a drinker of alcoholic liquors, of tea or coffee, and how strongly addicted to them, and the same regarding smoking; habits of exercise, whether regular, violent, and how taken; general health, whether robust or

senses,