below its foundations, creeks sable as ink surrounding it, and the ground unctuous with black fat alluvium." Not a pleasant place to live in, one would say, but healthy, nevertheless. This is a curious condition of affairs, and deserves to be carefully studied by some disinterested person of scientific attainments. In summing up a fifty-page argument, written to prove that the climate is not so much at fault as the individual, Mr. Stanley practically admits the unhealthiness of the whole region. "One more observation," he says, "will suffice. However well the European may endure the climate by wise self-government, years of constant high temperature, assisted by the monotony and poverty of the diet, cannot be otherwise than enervating and depressing, although life may not be endangered. To preserve perfect health, I advise the trader, missionary, coffee-planter, and agriculturist, who hopes to maintain his full vigor after eighteen months' residence, to seek three months' recreation in northern Europe." What a prospect to hold out to the emigrant! Three months out of every twenty-one to be passed away from his business or farm! Would not the expense of such journeyings eat up the profits of the eighteen months of hard work? And how about wife and children? Are the settlers of Kongo State to be bachelors? or are they to be at home only in those three months passed in northern Europe?

Mr. Stanley has not improved as a writer during the last six years. His volumes are full of descriptions of the river and its banks. But they are not interesting, except for the amount of food for thought they contain. His tone, too, towards his understrappers, is very ungracious, to use no harsher term. The maps are excellent, although it is difficult to see why the eastern half of the large map was not extended to the ocean; and a map on a larger scale of the country around the Livingstone Falls should have been added. With a few exceptions, the illustrations are wretched. They will not bear a moment's comparison with those in H. H. Johnston's 'Congo from its mouth to Bolobo.' Only seventeen out of the hundred and twenty-two are stated to have been made from photographs or sketches. The rest seem to have been drawn on demand, so to speak, in London. The wood-engraving, too, is very poor, the pictures having a hard and flat appearance that is unpleasing to the eye; while the flamboyant cover-design of a negress poised on the Belgian coat-of-arms defies description, and must be seen to be appreciated.

- The Macmillans have just issued an Elementary algebra for schools,' the joint work of Mr. H. S. Hall, assistant master at Clifton College, and Mr. S. R. Knight, late assistant master at Marlborough College, - a work which is said to differ in some important respects from the text-books now in use. The same publishers also announced a Treatise on differential equations,' by Mr. A. R. Forsyth, Fellow of Trinity College, Cambridge, and an 'Arithmetic for schools,' by the Rev. J. B. Lock, whose works on trigonometry have been favorably received.

-The schooner Rosario, at New York, reports that on June 23, in lat. 29° 14′ N., long. 133° 35′ W., at 11 A.M., two heavy shocks of a submarine earthquake were experienced. These were about one minute apart; and the last was much heavier than the first, causing the vessel to tremble violently. The sky was overcast, and the sea remarkably smooth. -Among the French species of the genus Polygonum, hybrids are rare in a state of nature; although there are two kinds of flowers, one fertile, the other sterile. In reply to some criticisms upon Gandoger's work on this group, he replies that this fact does not necessarily mark a degradation, but simply a different aptness in fecundation among different flowers; and that, although the absence of fertile grains point toward hybridity, this is not a sure sign.

--

-As much of recent geographical discovery in Asia has been due, says the Athenaeum, to native explorers trained in the surveyor-general of India's department, it will be interesting to place on record a list of the rewards lately granted by the government of India to some of the more prominent of these pioneers of Indian commerce. The most distinguished of them all, A. K., has received the title of Rai Bahadur, and with it a jaghir of rent-free land. The explorer known as 'the Bozdar' has been made a Khan Bahadur, and he also has received a grant of land. The Meah,' who accompanied Mr. McNair in his journey to Kafiristan, has been rewarded with a sum of money, and the same recompense has been given to A. K.'s companion; while a piece of plate has been presented to Mr. Penny, a planter who afforded the survey-officers much assistance during the Aka operations.

180

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FRIDAY, SEPTEMBER 4, 1885.

THE FUTURE OF THE LICK OBSERVATORY.

THE history and description of this observatory, and the astronomical work already accomplished on Mount Hamilton, which we have given on a later page, lead very naturally to a statement of the chief advantages which, in so far as the observatory and its position and equipment are concerned, may reasonably be expected to accrue from this new departure in astronomical science.

The fact of mere elevation (less than a mile) above the sea-level will not, as is often supposed, greatly increase the apparent light of celestial objects, as the stars will appear to be only a small fraction of a magnitude brighter on the mountain than at the sea-level. But - what is incomparably more important the gain in steadiness of the atmosphere at this elevated station has already been proven to be much greater than any one expected at the outset, and will enable the astronomer not only to make good use of a multitude of clear nights which, at less elevated stations, are found to be of little value, but also to elevate the grade of all his work to the last degree of precision. The perfection of this site for observations with the meridian circle - in fact, for all micrometric observation of whatever sort - will force the invention of better methods of eliminating personal and instrumental errors than we now possess. So far as the conditions of vision affect the stars' diurnal motion, the errors introduced in stellar co-ordinates will be so small that two or three observations of a star will suffice for the most accurate determination of its position. An enormous saving in the labor of observation and reduction is thus possible, if only the other errors can be eliminated with certainty from so small a number of observations. With regard to the influence of elevation upon the conditions of day-vision, it should be noted here that the testimony of Mr. Burnham in 1879, of Professor Holden in 1881, and of Professor Todd in 1882, is uniformly to the effect that the atmosphere above Mount Hamilton is quite as unsteady during the daytime as at other stations. This remark, however, must be understood as applying only to the period of the year from the

No. 135.1885.

middle of August to the middle of December, as no accurate observations upon this matter have been made in other months. It is very possible that the conditions of the atmosphere in late spring and early summer may give an entirely different experience at these seasons.

The elevation above a mile of the lower atmosphere becomes significant in another way, however, as it makes effectively available a much larger region of sky than can be commanded at other stations in a like latitude, where observations at zenith distances much greater than seventy degrees are usually not worth the making. Mr. Burnham directs attention to this fact, as affecting observations in that portion of the southern celestial hemisphere which is ordinarily inaccessible for observations of precision at our northern observatories. At the latitude of Mount Hamilton, the fifty-third parallel of south declination is about co-incident with the south horizon; and, out of forty-two new doublestars discovered by Mr. Burnham during his residence upon the mountain in 1879, twenty are between the thirtieth and fortieth parallels of south declination (that is, between limits of maximum altitude equal to twenty-three and thirteen degrees); and five of the new stars are between the fortieth and forty-fourth parallels, or between limits of maximum altitude equal to thirteen and nine degrees only. This important advantage will not be confined to the southern horizon only, but will duly influence all fields of astronomical inquiry where important observations have occasionally to be taken near other parts of the horizon.

The prevalence of violent winds on the summit, and particularly their effect upon the steadiness of the atmosphere, have not yet been thoroughly investigated. As a general rule, astronomers at ordinary elevations expect to find severe winds accompanied by atmospheric conditions which do not admit of satisfactory micrometric work. Mr. Burnham found that moderately strong winds did not seem to affect the optical steadiness of the atmosphere. A remarkable experience of my own on the mountain may be mentioned here. On the night of the 2d of December, 1882, when the wind was blowing steadily with such violence as to make it extremely hazardous to open the dome in the face of it, I found Jupiter and Saturn very unsteady and much

blurred; but turning to Sirius, I found the companion an extremely conspicuous object,

in fact, the note in my observing-book is to the effect that the companion was as readily seen as a satellite of Jupiter." So far as I am aware, this is a unique experience of the effect of severe wind upon the optical quality of the atmosphere.

The location of the observatory in a region which is entirely cloudless during the greater part of the year, constitutes an advantage which only those can fully appreciate whose work has suffered serious interruption from the lack of a continuously clear sky. Should those permanently in charge of the observatory find it desirable to continue observations throughout the period of five months known as the rainy season,' it would doubtless be found that the superior elevation would afford a clear sky throughout one-third to onehalf of this period, and simultaneously with clouds and storms at stations lower down. During my own residence on the mountain in the latter part of 1882, and shortly after the beginning of the rainy season, this was frequently the case; and on two separate occasions we were favored with an uninterruptedly clear sky for more than seventy consecutive hours, being situate on an island in a sea of cloud which obscured every thing beneath the immediate summit. A series of excellent photographs of this cloud-sea was obtained, one of which is well reproduced in the illustration on p. 191. Ocean fogs rarely reach the elevation of the observatory. Mr. Burnham observed these fogs drifting in from the Pacific nearly every night at about the time of sunset. Their usual altitude was about two thousand feet, and they did not appear to affect the seeing.

The instrumental equipment of the observatory, although incomplete, is already an unusual one, and, in its final state, will surpass that of all other observatories. The instruments have been designed, constructed, and mounted in the most thorough manner; and particular care has been taken that all the movable portions of the buildings covering these instruments (always a source of unending trouble and vexatious delay to the astronomer) shall be so arranged and constructed as to cause a minimum of annoyance and interruption.

The great advantages arising from the observers' ability to reside near their instruments must not be overlooked here. A suitable dwelling-house for the observers has been provided in the immediate proximity of

the instruments, so that all the time available for observatory work may be fully utilized.

The means of publication -a most important consideration in the management of a great observatory-has not escaped due notice. The legislature of California has already shown its entire appreciation of the observatory and its work, by the passage, at its last session, of a joint resolution providing for the issue of such reports, observations, and researches, as may, with the approval of the governor of the state, be submitted by the Lick trustees, or the regents of the university, for publication.

Finally, and most important of all, there is an assured endowment of generous proportions, the income from which is wholly available for the maintenance of the establishment, and the prosecution of its work. The considerate management of the trustees will enable them to complete the observatory at a cost not much exceeding three-fifths of the entire allotment of Mr. Lick's bequest for this purpose, and the remainder will constitute the permanent endowment-fund of the institution.

Fortune and necessity, however, do not fail to accompany this unique combination of opportunities with more or less of disadvantage. The unavoidable obstacles of the undertaking have been great, but they have also been surmounted. But the necessary expense of maintaining so large an establishment at so elevated a station, the cost of living, the social isolation of the astronomers, amounting to practical exile for months at a time when series of observations requiring uninterrupted attention are in hand, - these, and other obvious considerations, must be carefully considered by any one who attempts a fair estimate of the work which the Lick observatory is destined to accomplish. While it appears that the institution will be in a strong position to conduct and maintain a good degree of astronomical research with its own resources, there will be abundant field for prudent financiering in the management of its practical affairs. However, when the trustees are ready to resign the control of the observatory, the character of its instrumental and other equipment will be such that all increase of its permanent income, derivable from outside sources, will be wholly available for the pursuit of new and interesting lines of research. The nature of investigations of this sort enables the astronomer to make successful appeal for the funds necessary to carry them on; and the trustees have wisely refrained from equipping the observatory with any instruments and apparatus which will