84 



NA TURE 



[May 28, 1896 



centre of study and research in paleontology. Increasing interest 

 in the Museum has been evinced by all classes of the citizens of 

 New York. Ever)' course of lectures has been attended by 

 crowded audiences, and pupils of public and private schools, as 

 well as students of science, have derived advantage from the 

 library as well as from the collections. 



Several new editions of scientific works have reached us 

 during the past few days. The first volume of a new edition of 

 Prof. Fleming's systematic treatise on " The Alternate Current 

 Transformer," dealing with the induction of electric currents, 

 has been published by the Electrician Printing and Publishing Co. 

 The great progress made during the seven years which have ela])sed 

 since the appearance of the original work, has necessitated a 

 thorough revision of the matter, and the volume as it stands now 

 will be appreciated by all who are concerned with alternating- 

 current practice or investigations. Another volume having 

 practical electricity for its subject is " Electric Lighting and 

 Power Distribution " (VVhittaker and Co. ), by W. Perren May- 

 cock. The first volume of the third edition of this work has 

 been issued in an enlarged fftrai, after careful revision. The 

 second edition of the first volirme of Dr. Schlich's '' Manual of 

 Forestry" has been published by Messrs. Bradbury, Agnew, 

 and Co. The original was reviewed in Nature in December 

 1889 (vol. xli. p. 121), and quite recently (April 2, p. 510) was 

 referred to in these columns. The second edition contains a new 

 part on the State in relation to forestry, and a general review of 

 the timber requirements of the British Empire. Messrs. Long- 

 mans, Green, and Co. have issued a second edition of "The 

 Essentials of Chemical Physiology," by Dr. W. D. Halliburton. 

 The chief alterations made are those rendered necessary by the 

 advance of knowledge since 1893, when the first edition was 

 published. The fifth edition of " Southall's Organic Materia 

 Medica," by J. Barclay, has been published by Messrs. J. and 

 A. Churchill. To quote the sub-title, the volume is "a hand- 

 book treating of some of the more important of the animal and 

 vegetable drugs made use of in medicine, including the whole of 

 those contained in the British Pharmacopoeia." New editions 

 of two volumes by the late Dr. J. E. Taylor, have been received 

 from Messrs. W. H. Allen and Co. The books are " Nature's 

 Byepaths," a series of recreative papers in natural history, and 

 " The Aquarium," a popular manual on the history, construction, 

 and principles of management of public aquaria. Dr. G. 

 Herbert Fowler has edited the sixth edition of the late Prof. 

 Milne Marshall's valuable work on the anatomy, histology, aifa 

 dembryology of "The Frog" (Dayid Nutt). A few additions 

 and alterations have been made, but the work remains substan- 

 tially the same practical and educational handbook that it ever 

 was. Finally, the recent changes in the Physiography Syllabus 

 of the Department of .Science and Art have resulted in the pro- 

 duction of a new edition (the sixth) of " Earth Knowledge" 

 (Part II.) by W. Jerome Harrison and H. R. Wakefield. The 

 book follows the Department's Advanced Syllabus, and appears 

 to fulfil the purpose for which it has been designed. 



The additions to the Zoological Society's Gardens during the 

 past week include a Macaque Monkey {Macactis cynomolgus) 

 from India, presented by Sir William Call ; a Blue-bearded Jay 

 (Cyanocorax cyaiwpogaii) from Para, presented by Mr. H. C. 

 T. Beadnell ; four Puff Adders ( Vipera arietans), two Ring- 

 halsl^Snakes [Sepcdon /iieinacliaies), an Egyptian Cobra {JVaia 

 haje), three Cape Vipers (Causus rkombeatiis), a Cape Buce- 

 phalus (Bucephalus capciisis), two Infernal Snakes {Boodon 

 infenialis), a Nilotic Monitor ( V'aranus iiiloticiis) from South 

 Africa, presented by Mr. J. E. Matcham ; a Chey Ichneumon 

 {Herpestes grisetis) from India, deposited ; two Indian Tree 

 Ducks {Dendrocygna javanica) from India, purchased ; a 

 Japanese Deer [Ceii'iis silta), born in the Gardens. 

 NO. 1387. VOL. 54] 



OUR ASTRONOMICAL COLUMN. 



Tempera'iuke Errors in Meriiuan Observations. — M. 

 Hamy has applied his method of interference fringes to a study 

 of the errors caused in meridian observations by the radiations 

 of the sources of light usually employed in observatories, as 

 well as those due to the presence of the observer himself (Bull. 

 Ast., vol. xiii. p. 178). The researches have completely demon- 

 strated that the unequal distribution of light sources may produce 

 errors in the measures amounting to several seconds of arc, while 

 the heat from the observer may affect the results to the extent of 

 several tenths of a second. It is evident therefore that the sub- 

 ject is one of great importance, and the interferential method is 

 specially adapted for its investigation. M. Hamy has arrived 

 at his conclusions from experiments made with the Gambey 

 meridian circle of the Paris Observatory. In the case of an 

 ordinary gas flame at a distance of o'83 metre from the 

 telescope, the mean angular displacement of the optic axis with 

 respect to the meridian amounted to 2"'i, the flame being lit for 

 ten minutes. Other observations indicate that the deviation is 

 sensibly in inverse proportion to the square of the distance of 

 the flame from the optic axis. The effects of different sources 

 of light were also compared at one metre distance, and the 

 practical outcome is that gas flames provided with chimneys are 

 to be studiously avoided, the variation in collimation amounting 

 in this case to 4" '4. The errors due to the heat of the human 

 body are greatest in the case of declination measures, owing to 

 the greater heating of the under side of the telescope tube. It 

 is evident that these errors will depend to some extent upon the 

 materials of which the instrument is constructed, and M. Hamy 

 is of opinion that the best possible material is a metal of high 

 conductivity, such as copper, in which case inequalities of 

 temperature would be almost impossible. 



Search Ephemeris for Comet 1889 V. — The following 

 is a continuation of Dr. Bauschinger's search ephemeris for the 

 return of Brooks's periodic comet (1889 V) (Ast. Nach,, No. 



335°)- 



R.A. Decl. Bright- 



May 28 ... 22 2 38 



June I ... 7 17 



5 ■■ "43 



9 ■•■ 1554 



13 1949 



17 ... 2326 



21 ... 2644 



25 ... 222944 



19 44 ... 0-44 



19 29 0-48 



19 14 ... 0'52 



19 I ... 0-56 



18 49 ... o'6i 



iS 39 ... 066 



18 30 ... 071 



18 22 ... 077 



The unit of theoretical brightness is that on 1S89 July 8, the 

 date of the first accurate observation. The comet was last seen 

 in January 1891, at the Lick Observatory, when the calculated 

 brightness was only 008. During June the computed path lies 

 in the southern part of Aquarius, so that observations can only 

 be made in the early morning. 



Constants for Nautical Almanacs. — At a conven- 

 tion of Directors of Nautical .-Mmanacs, held at Paris after 

 the recent congress of the International Photographic Chart, 

 Dr. Gill's value of the solar parallax (S"'8o), resulting from 

 heliometer observations of minor planets, was adopted, and 

 consequently the constant of aberration becomes 2o"'47. Dr. 

 Gill's value for the mass of the moon, leading to 6" '21 for the 

 nutation, was also adopted, and Newcomb's value was accepted 

 for the precession. 



The Planet Mercury. — A postcard from Dr. Kreutz, 

 Kiel, contains the information that Mr. Leo Brenner, of the 

 Manora Observatory, saw the dark part of the planet Mercury 

 sharp and di.stinct on May 18, at 23h. Manora time. 



STELLAR PHOTOGRAPHY WITH SMALL 

 TELESCOPES WITHOUT DRIVING-CLOCKS. 

 CTELLAR pliotography has now become such an important 

 ^■^ branch of astronomy, that anything which will encourage 

 possessors of small telescopes to turn their energies in this direc- 

 tion will tend towards the advancement of the celestial sciences. 

 It is proposed to show here that useful work may be done by 

 amateur astronomers with their ordinary small refractors, and 

 with none of the mechanical contrivances which are essential for 

 such large telescopes as are used in the international photo- 

 graphic survey of the heavens, which are driven by elaborate and 



