successfully bringing about the explosion, so graphically described in Colonel McFarland's letter.

From the stand-point of an outside would-be observer, the story of the Flood Rock explosion may be told as follows. The idea of determining the velocity of the vibrations through the ground was suggested at a late date, and the preparations were necessarily hurried and incomplete. No official information could be obtained, fixing even approximately the date of the explosion, and we were obliged to depend upon the newspapers for that information. Near the end of the week preceding its occurrence, the papers announced that the time was set for Wednesday, October 7, at 9 A.M. We hurriedly collected the apparatus prepared to date, boxed it, and shipped it to New York on Monday the 5th, and were to follow it that night, when the evening papers announced a postponement probably till Saturday the 10th. Nearly all the astronomical observatories within 200 miles of New York had been invited to co-operate (see Science, vi. 327), and had been asked to watch the New York papers, and been promised a telegram several hours before the event. fixing, if possible, the nearest minute at which it would occur.

The announcement and warning by General Newton on the afternoon of Thursday the 8th, together with a letter at the same time to the representative of the geological survey, were the first information we had of the time set for the explosion.

I would say that General Abbot cordially cooperated with us, and that his offer to send his timesignals to the Western union office (after the explosion) was duly appreciated. We did not take advantage of it, however, as it would have been very troublesome to distribute signals to fourteen observatories or institutions scattered in all directions over an area of 200 miles radius, and it was entirely unnecessary, as every one of them had the means of determining standard time for itself, or was in daily receipt of standard-time signals at noon. With the delay in the time of firing, of which we do complain, we understand that General Abbot had nothing to do.

It should be distinctly noted that the engineer observers within sound of the telegraphic ticks from the chronometer at Astoria, and waiting for the preliminary automatic signal from the firing-key, were in a vastly more favorable position in case of delay; and if this had been anticipated, and there had been time and opportunity to distribute the chronometer ticks and firing-signal to all the outside stations, of course it would have been done.

Regarding the observations cited by Colonel McFarland as having been successfully made at Columbia college, Yonkers, Princeton, and Cambridge, I would say that, at the first two, it was due to their proximity, while, in view of Professor Young's description of the Princeton observations (Science, vi. 335), it seems somewhat of a strain upon the meaning of language, unless used in some approximate, engineering sense,- to call them a success; and at present the writer considers it somewhat doubtful if the Cambridge observations refer to the explosive wave. The statement that the two officers at Willet's Point would have watched an hour, if necessary, only goes to show how much better posted the engineer observers were as to a possible delay in the firing.

As to my own observations at Staten Island, their failure is of itself of little importance, but it is to me a source of wonder and sincere admiration to see

how much more an engineer officer can know about them than the observer himself. They will be described in due time with the other reports. At present I can only say that under the same circumstances, if endowed with only the same degree of intelligence' I then possessed (even after a study of the Hallet's Point explosion of 1876), I should probably do just the same again; but, with the rapid growth since Oct. 10 of my knowledge of engineering science, I can hardly state now how long I would not wait for the occurrence of a definitely predicted engineering phenomenon.

Suffice it now to say that eight out of the seventeen stations were successful in observing either the first arrival or the pretty certain non arrival of the vibrations. The others were all thrown off by the delay, combined, in four cases, with observation of earth-tremors occurring at several places during the first ten minutes after eleven. It would almost seem as if the earth itself were, about that time, growing uneasy at the delay in the oncoming of the dread event. H. M. PAUL.

Washington, Nov. 9.

The arms of the octopus, or devil fish. Prof. T. Jeffrey Parker (Nature, October 15, p. 586) refers to an octopus of the New Zealand fauna, with arms five feet five inches long, as the longest seen by him, and as exceeding what Mr. Henry Lee calls the longest-armed octopus known, namely, that from Vancouver Island, which had arms five feet long.

In 1874 I speared an octopus in the harbor of Iliuliuk, Unalashka, which was afterward hung, by a cord tied around the body immediately behind the arms, to one of the stern davits of the coast survey vessel under my command. As soon as the animal died and the muscles relaxed, I noticed that the tips of the longer tentacles just touched the water. On measuring the distance with a cord, I found it to be sixteen feet, giving the creature a spread from tip to tip of the longest pair of arms, of not less than thirty-two feet. The arms toward the tips were all exceedingly slender, but rather stout toward the body, which was somewhat over a foot long. The largest suckers were two and a half inches in diameter; the whole creature nearly filled a large washtub. Parts of this specimen are now in the U. S. national museum. Having heard octopi were eatable, and the flesh looking white and clean, we boiled some sections of the arms in salt and water, but found them so tough and elastic that our teeth could not make the slightest impression on them. WM. H. DALL.

FRIDAY, NOVEMBER 13, 1885.

THE RESULTS OF SHAD PROPAGATION ON THE ATLANTIC COAST.

AT a recent meeting of the Biological society of Washington, Col. Marshall McDonald read a paper upon the necessity of artificial propagation, in relation to the maintenance of the shad fisheries.

fluctuates under local conditions. It is not true that shad, spawned in certain rivers, necessarily return to the same rivers. They remain, it is true, in the geographical area in which they were spawned, but may seek any fresh water within that area. It is only by taking the statistics of the rivers of the entire area that it could be determined whether there had been an actual increase or decrease. Table I. giving "Comparative statistics

21% Decrease.

Remarks.

20% 67% of all shad taken in the Increase. Chesapeake and its tributaries in 1885 were taken in salt or 65% brackish water before reachDecrease. ing spawning grounds. 74% The 33% taken by the river Decrease. fisheries on, or in the vicinity 86% of, their spawning grounds, Increase. being captured for the most part before they had spawned, it will be seen that we are de131% pendent for natural reproducIncrease. tion upon the small number of shad that escape the pound nets and elude the energetic pursuit of the river fishermen.

He argued that the shad fisheries depend upon artificial production for their maintenance. This theory was illustrated by a comparison of statistics for 1880 and 1885, and a consideration of the attendant conditions. The figures for 1880 were taken from the census reports; those for 1885 from a recent reconnoissance by experts, usually the same persons who made the census reports. He brought together the statistics of all the rivers of the Atlantic slope. The catch in each river

of the shad fisheries of the Atlantic rivers," was submitted.

While the commercial value of the increase was not large compared with the whole, that sum was ten times as great as the yearly sum spent by the fish commission upon the work of propagation.

In order to arrive at a measure of the increase or decrease of the shad fisheries of the Atlantic coast rivers, it is necessary to compare the aggregate catch in the principal rivers. Conclusions

based upon the fluctuations of catch in a single river are necessarily fallacious, since such fluctuations are due to local causes. So far as the shad is concerned, all the rivers draining into the Atlantic between Cape Cod and the capes of the Chesapeake, and the submerged continental borders lying between the coast line and the Gulf Stream, constitute a single zoological province, within the limits of which the migrations of the shad are confined.

In February and March, when their migrations into continental waters begin, the direction of their movements is largely determined by temperature conditions existing in the area in which they are. The principal migration may be into the Chesapeake, or it may be up the coast into the Delaware, the Hudson, and the Connecticut; but in either case the aggregate catch will furnish a just measure of increase or decrease. A comparison of the statistics of the fisheries for 1880 and 1885 (see table I.) shows a gain of nearly eight per cent in the aggregate catch. The significance of this, as showing the value and necessity of artificial propagation, will be better appreciated by considering the adverse conditions under which it has been accomplished :

1. Access to suitable spawning grounds in fresh water is a physiological necessity.

2. Access in sufficient numbers to compensate by natural reproduction, waste by casualty or capture, is necessary to prevent the eventual destruction of our shad fisheries if we rely upon natural reproduction solely.

3. Existing adverse conditions limit natural reproduction, so that we cannot depend upon it to keep up supply.

(a) Dams in our rivers have curtailed the spawning areas to less than half of what they formerly

were.

(b) The spawning grounds still accessible have been destroyed by the pollution of the waters, which are thus rendered unfit to sustain the delicate embryo shad.

(c) The change in the location of the fishing grounds, and the increasing proportion of shad taken year by year outside of the mouths of the rivers, or in the rivers before they have reached spawning grounds, has so reduced natural reproduction as to render it an insignificant factor in keeping up supply.

Under such conditions, the spawning area being limited, and the shad excluded from fresh water, without artificial propagation, the shad must soon be exterminated, or there must at least be such reduction as to render the fisheries unprofitable. Such a crisis was fast approaching in 1879, when the fish commission began the work of shad propa

gation. The work of artificial propagation has not only held the balance even, but resulted in a slight increase.

Colonel McDonald deprecated the methods employed in shad fishing, especially the use of pound nets. In the Connecticut River, where pound nets are used, the greater part of the catch is taken in salt water. In the Hudson, since the laws of New York do not permit fishing with pound nets, the river is not obstructed to the same extent as the Connecticut. In the Delaware, where an increase is shown, there are no pound nets. In the Chesapeake and its tributaries, with a decrease of 21 per cent, 713,000 of the shad caught this year, or more than one-half of the whole catch, were caught in the salt water of the bay. The pound nets begin at the capes, and extend to the mouth of the Potomac. Prior to 1871 the shad were taken entirely in fresh water, but now over one-half are caught in salt water. In the Potomac River nearly one-half of the catch is made in water where the fish cannot spawn. In the Rappahannock one-half the catch is in brackish water. In the York River the catch is practically below Gloucester Point. In the James River there are no pound nets, and in that river is an increase in the catch. While the fisheries in the Chesapeake Bay and its tributaries, as a whole, have fallen off 21 per cent, the decrease in the catch in certain rivers is much greater. The catch in the Susquehanna in 1880 was 614,000, against 212,000 in 1885; and in the Potomac, 552,857 in 1880, against 157,697 in 1885. The reason of this is obvious. In 1871 there were no pound nets in Chesapeake Bay, and no shad were taken until they entered fresh water. Gilling was not prosecuted so low down the river as now. In 1880 there were in Chesapeake Bay 180 pound nets set in the track followed by the shad along the western shore, and through these the shad had to run a gauntlet up to the mouths of the rivers. Now there are 1,000 pound nets, occupying the western shores of the bay, and excluding the fish from the fresh water. The effect of the salt-water fishery is to diminish natural reproduction, and to invoke artificial propagation as a necessary aid to the fisheries. If all shad were excluded from our rivers for three or four years, without artificial propagation, the species would be exterminated. Taking all the facts into consideration, and the inadequacy of natural reproduction to supply the annual loss, we must credit artificial reproduction not only with having maintained the fisheries where they were, but with an increase which repays ten times the cost of the work of shad propagation, as carried on by the U. S. fish commission and those of the several states.

man.

INFANT PSYCHOLOGY.

THE modern psychologist must be a very busy We may suppose him to be a college professor, introducing his students into the principles of his science. Besides this, he is the director of a psychophysical laboratory, where he subjects himself and others to tortuous and tedious experiments, almost deserving the name of vivisection. Moreover, he must be intimate with the asylums for the insane and the idiotic, in order to study the mind in its morbid conditions; he must be at home in institutes for the blind and for deaf-mutes, in order to appreciate the role played by each sense in the sensual and intellectual life; he must talk to the inmates of prisons and poor-houses in order to understand the condition of those in whom the instinct of morality and the power of the will are at a low ebb; he must be active in psychic research and be ready to investigate the claims to unusual mental faculties; and now for what remains of his time, he is called into the nursery.

'Infant psychology' (by which name we must now know this field of study) has for its aim, the tracing of the mental development,-the psychical evolution, of the infant from birth upward. The literature of the science is as yet small; every single contribution, however, has been made by able hands; and the work of M. Perez' is a good type of this new tendency in modern psychology. In his former educational works as well as in his ingenious study of his two cats' (Mes deux chats), M. Perez has proved himself possessed of an unusual psychological acumen. We probably owe the ance of this book in an English dress to Mr. James Sully, who prefaces it with an appropriate introduction; great credit is due to the translator (Alice M. Christie) for her careful and easy rendition.

appear

It would be impossible here to do more than indicate the general lines of interest pursued in the book, and sample its method and wealth of facts. We may trace as many as five distinct interests which such study furthers :

1. It interests the pyschologist, as an important chapter in the study of mind, its psychogenesis.

2. It interests the anthropologist, to whom the remarkable analogy between the mental world of the child and that of primitive savages, is rich in suggestiveness. Impulsiveness and irascibility, to give one of a host of examples, are seen almost in the same aspect in savages and children. 3. It interests the alienist who finds, in the degeneration of mental tissue as shown in his insane patients, the same mental peculiarities, but occurring in a reverse order, as in the process of brain building in the

1 The first three years of childhood. By BERNARD PEREZ. Translated by Alice M. Christie, with an introduction by James Sully. London, Sonnenschein, 1885. 294 p.

child. The earliest memories are the last to fade away: the old man becomes childish. 4. It interests the student of comparative psychology, who notes the strong resemblances between the reasonings of the child and those of the higher animals. They fall into the same kind of errors and exhibit the same kind of peculiar tendencies; witness how often a child is called a 'monkey,' or a 'pussy.' 5. Lastly it interests the educator. The human child spends its first years in a condition of helplessness such as is seen in no other animal. It needs more watchfulness, more care, more education. To give this education, in a rational way, requires the study of the infant's mind, " for the cardinal principle of modern educational theory is, that systematic training should watch the spontaneous movement of the child's mind and adapt its processes to these" (Sully).-All of these will find that none of their points of view has been neglected in this book.

From

The scope of the work is wide: it covers really everything that can be called psychic in the first three years of life. Indeed the first chapter treats of the Faculties of the infant before birth.' its first cry on entering this world (which Schopenhauer takes as a pessimistic omen), his first movements, sensations, emotions, expression of will power, all are recorded and from them his mental status deduced. Systematic experiments are arranged and spontaneous movements and expressions noticed as well. The last chapters are devoted to the reasoning powers of children, their language, their logic, their æsthetics, their ethics, and, a very interesting point, their dramatic instinct.

Take the sense of taste for example. It is in the sphere of this sense that the child's first pleasure is felt, a few hours after birth, in the appeasing of hunger. At an early period disgust through taste is possible. A child 24 months old refused its bottle with determination and a face of disgust, because it was not sweetened with sugar. Illusions of taste appear early. The taste of children changes easily, which is a reason for not forcing them to eat things against their inclination. Its most vivid sentiments are for a long time connected with this sense. "Their first affections are those of an epicure; their first feelings of gratitude are awakened by the stomach; they test their first tactile experiences as much as possible by the sense of taste." Everything goes to the mouth. "Pretty to look at, and good to eat, are synonymous terms to babies." We can see how largely their earliest mental horizon is dominated by the feeling of hunger and the sense of taste.

The emotional life of the child begins early. Fear is one of its first emotions. Darwin has

noticed signs of fear at an unexpected noise or strange face in the first weeks. Between the 3d and the 10th months, fright is caused more often by auditory than by visual impressions. A child of 3 months showed no sign of fear at a conflagration, though surrounded by flames, until the noise of the fire engine was heard, and then he trembled and cried. Thunder terrifies rather than lightning. This is referred to as hereditary and the result of anterior experiences, which have "rather predisposed the race to listen for dangers which are near at hand, than to be on the lookout for distant ones." The reverse is true of most animals.

Finally as an example of the logical powers of infants, that of generalization will serve. Dogs generalize; they bark at all beggars; yet they distinguish one beggar from another on nearer approach. A child had a tin box into which he used to delight to stuff things; he soon found that other of his toys had the power of holding things; then he tried to find an opening in everything, into a glass stopper because it was transparent; in short, he had acquired a general idea of an opening. Another child had a canary named 'Koko'; when he saw chickens in the yard or ducks in the pond, they were Koko' too. While these young children generalize before the acquisition of language, they do not compare. A child was shown a print and stretched out her hands for it; then a colored print was shown; her joy was beyond bounds. In a second experiment both were shown at once; she took them for one picture and threw herself towards both; her attention was not directed to the brighter one. These illustrations are doubtless sufficient to indicate the character of the volume.

The record of one or two infants is naturally unsatisfactory; individual peculiarities are certain to enter. What is wanted is a collation and average of many observations. For England, Darwin and Pollock, for France, Taine and Perez, for Germany, Tiedemann, for Austria, Preyer, for Italy, Ferri, have contributed to this study. May we not soon expect to hear as to the psychology of the American baby? J. JASTROW.

LEGAL OHM STANDARDS. AFTER the decision of the Paris electrical congress of 1884, that the standard resistance, or legal ohm, should be the resistance of a column of mercury of one square millimetre cross-section, and 106 cms. in length, at zero centigrade, it became necessary to construct standards that should represent this resistance. In France this task was intrusted by the minister of posts and telegraphs to M. J. R. Benoît; and in England Mr. R. T. Glazebrook, at the request of the electrical stand

ards committee of the British association, undertook the same work.

M. Benoît attacked the question ab initio. From a large number of glass tubes, of about 120 cms. length, and 1 mm. diameter of bore, the four that had the most uniform bores were selected. These tubes were laboriously calibrated to determine the cross-section at every point, and each was then cut off so that the resistance of the column of mercury filling the tube should be as nearly as possible the same as that of the column defined as the standard. The points where the tubes were cut off were determined from the calibration. The resistance of each tube was then calculated from its dimensions, with the following results : Tube 10.999999 legal ohms. 21.000004 99 30.999979

Accepting these as the true resistances, M. Benoît made a number of secondary standards, of glass tubes doubled upon themselves and bent into compact forms, and with cups at each end for making contact. The resistances of these tubes, when cleaned and filled to certain marks on the cups with pure mercury, were determined by comparison with the primary standards mentioned above.

Mr. Glazebrook considered it unnecessary, for the construction of the required standards, to go through the laborious process adopted by M. Benoît, for the specific resistance of mercury had been determined in terms of the British association standards, in several elaborate investigations by Lord Rayleigh. Mascart, Strecker, and others, and so based his standards on the value of the resistance of mercury adopted by the British association committee; viz., a column of mercury at zero centigrade, one metre long, and one square mm. cross-section, has a resistance of .9540 B. A. units.

Mr. Glazebrook has made a careful comparison of his legal ohm standards with those made by Benoît, and finds that there is a difference of .0005 ohms between them, the Benoît standards being less by that amount.