Feb. 



1887] 



NA TURE 



m 



It is proposed that a school of hygiene shall be established at 

 the University of Michigan, and the State Legislature is about 

 to be asked to authorise the necessary expenditure. The scheme 

 was suggested by the State Board of Health. The school 

 would include in its curriculum cliniatological st udies, air an;ily-.i.'s 

 and ventilation. 



Last week there was a Convention of Photographers in the 

 Hall of the Society of Arts, and the attendance was good and 

 representative. The proceedings in the morning were openeil 

 by a few remarks from Capt. Abncy, the President, who, in 

 the afternoon, delivered a more elaborate address, projecting on 

 a screen a succession of diagrams and pictures illustrative of his 

 statements. At a dinner in the evening the tc-ist of the Camera 

 Club H\Ti proposed by Mr. V. lilanchard, who, in recalling the 

 time when he made his first practical acquaintance with photo- 

 graphy by watching a friend develop a paper negative, expressed 

 the opinion that photographers might perhaps return to the use 

 of paper negatives. 



Prof. Liversidge, of the University of Sydney, who is 

 about to return to England on leave of absence, has been 

 requested by the Minister of Public Instruction of New South 

 Wales io inquire into and report upon the mode of teaching 

 natural science in the elementary schools of Great Britain and 

 Ireland. 



New Sduth Wales will- be represented at the Conference 

 of Astronomers to be held in Paris in April next, by Mr. H. C. 

 Russell, the Government Astronomer. 



A VALUABLE " Report on the Medusae collected by the U.S. 

 Fish Conunission Steamer Alhalross, in the Region of the Gulf 

 Stream in 1883-84," by Mr. J. Walter Fewkes, has lately been 

 reprinted, at the Government Printing Office, Washington, from 

 the Annual Report of the Commissioner of Fish and Fisheries 

 for 1884. Mr. Fewkes is not sure that certain of the Medusx 

 recorded by the ChalUnger from great depths do not also live 

 and flourish at or near the surface. There is need, he thinks, 

 for greater accuracy in the determination of the exact depth 

 from which a deep-sea Medusa is taken, and for an improve- 

 ment of the apparatus used in this kind of collecting. In 

 the case of fixed hydroids, or such Medusa as Cassiopeia 

 and others, which live upon the bottom, the determination 

 of the depth at which they live is an easy task. With such 

 genera as Atolta, Khizophysa, and others, this determination is 

 more difficult. Mr. Fewkes points out that it is of great im- 

 portance, from a morphological stand-point, that the question 

 whether Medusje are confined to certain depths, should be defi- 

 nitely answered. "'I can at present," he says, "imagine no 

 place on the globe where the uniformity of conditions under 

 which Medus.v are placed can be the same as at great depths of 

 the ocean. I do not mean necessarily on the Hoor of tite ocean, 

 since that may be raised or depressed, and the varieties of con- 

 ditions which come from such motions may result, but in the 

 depth of the sea, separated from the surface by a wall of water 

 of great depth, and from the ocean-bed by a similar wall of 

 equal amount. Here, if anywhere, may we look for the con- 

 tinuance of ancestral features unm idified by environment. t)n 

 this account the determination of the bathymetrical limits of 

 free Medusic, no less than that of those animals which inhabit 

 the bottom, is a most important thing, and from it should be 

 eliminated all possibility of error." 



Dr. Otto Hermes has just published the results of some 

 interesting investigations concerning the phosphorescence of 

 marine fish. He wished to ascertain whether the phosphores- 

 cence was caused by the same Bacillus which Dr. Fischer, an 

 eminent authority on Bacteria, has discovered and brought from 

 the West Indies. Marine fish are easily rendered phosphorescent 

 after death by being moistened with a little sea-water. Dr. 



Hermes took a fragment of a specimen of Gains callarias, which 

 had been made strongly phosphorescent in this manner, to the 

 laboratory of Councillor Koch ; and Dr. Frank, a pupil of the 

 latter, was enabled to isolate it after a few days. This is un- 

 doubtedly a new species. Like Dr. Fischer's Bacillus, it can 

 be transferred upon sterilised fish, and after forty-eight hours it 

 emits an emerald-green light ; the sea-water is also rendered 

 phosphorescent. A point of difference is that the Bacillus of 

 Dr. Fischer develops best in a high temperature {2.0' -22.°), while 

 that of Dr. Hermes develops better in a low one. Examined 

 microscopically, the latter is much smaller than the former. Dr. 

 Hermes has given it the name of Bacterium pitospkorescens. 



The German Fishery Association lately asked the German 

 Chamber of Commerce to put a premium on seals, it being main- 

 tained that these animals are most destructive to the fisheries. The 

 petition was refused. The Association, in support of its views, 

 stated that a full-grown seal requires 10 lbs. of fish a day for its 

 food, making 3650 lbs. in a year. At the same rate, 1000 seals 

 would consume the enormous quantity of 3,650,000 lbs. a year. 

 As the seal is a faithful attendant upon herring-shoals, it causes 

 enormous havoc among a species of fish which is one of the 

 greatest sources of revenue to the fishermen on the North Ger- 

 man co.ast- It is maintained that these depredations have greatly 

 decreased the quantity of fish in recent years. Complaints ot 

 the serious destruction of fish by seals have also lately been made 

 by Swedish fishermen in the Baltic. 



The additions to the Zoological Society's Gardens during the 

 past week include a Green Monkey {Cercopithcciis caililrichus S ) 

 from West Africa, presented by Mr. Charles W. Demprey ; a 

 Bounet .Monkey {.l/acaeiis siniais S ) from India, presented by 

 Mr. G- S. Copeland ; a Common Otter {Liitra vulgaris), 

 British, presented by Mr. John Hall ; two Rufous Tinamous 

 {Rhynclwtits i-ufescens) from Brazil, presented by Mr. Francis 

 Monckton ; two White-throated Finches (Spermophila albogu- 

 laris i 9 ) from Brazil, deposited; a Collared Fruit Bat (Cyno- 

 nycleris col/aris), born in the Gardens. 



OUR ASTRONOMICAL COLUMN 

 A Method for the Determination of the Constant 

 OF Aberr.\tion. — Referring to M. Loewy's plan for the deter- 

 mination of the constant of aberration by measuring the relative 

 positions of stars situated in distant parts of the sky at succes- 

 sive epochs by means of a double mirror placed in front of the 

 object-glass of an equatorial (Nature, vol. xxxv. p. 282), M. 

 Houzeau points out (Comptes reiidus, tome civ. No. 5) that the 

 same idea occurred to him some years ago, and that the funda- 

 mental principle of the method, and an enumeration of the 

 advantages attending its application, were pubhshed by him in 

 1871, in a paper entitled " Considerations surl'Etude des petits 

 Mouvements des Etoiles," which appeared in tome xxxviii. of 

 the Memoires de 1' Academic de Belgique. It appears, there- 

 fore, that M. Loewy's method cannot, strictly speaking, be con- 

 sidered a new one, though we believe it has never been put into 

 actual practice — a work which we hope to see before long accom- 

 plished at the Paris Observatory. 



The Application of PHOTOORArHY to the Determina- 

 tion OF Stellar Parallax.— In the Monthly Notices for 

 January 18S7, Prof. Pritchard publishes the results of his mea- 

 surements of the photographs of 61 Cygni and neighbouring 

 stars, taken on fifty nights ending December 7, 1886, with a 

 view to the determination of the parallax of this well-known 

 star. Using measures of distance only, the relative parallaxes 

 of each of the components, referred to each of four comparison- 

 stars, are : — 



Parallax of 

 61^ Cygni 



0-4412 

 •4529 

 •4433 



■4 '58 



00154 



•0330 

 •0197 

 •0161 



Parallax of 

 6i- Cygni 



o"4204 



•4139 

 •4721 

 ■4574 



00229 



•0185 



■0215 

 0252 



