August 30, 1894] 



NATURE 



43- 



a statistical report on the fisheries of the Gulf States, by Mr. J.W. 

 Collin> and Dr. II. .M. Smith ; a report on a collection of fishes 

 from the Albemirle region of North Carolina, by the latter 

 author ; a paper on the spawning habits of the shad, by Mr. 

 S. G. Worth ; a report on the aquatic invertebrate fauna of the 

 Yellowstone National Park, and of the Flathead region of Mon- 

 tana, by Prof. S. A. Forbes ; and a report on the fisheries of 

 the South Atlantic States. Finally, the volume contains a 

 description, by .Mr. Bashford Dean, of the methods of oyster- 

 culture in Italy, Spain and Portugal, Germany, Holland, 

 Belgium, and England. Oyster-culture, as practised in France, 

 had previously been reported upon in connection with the U.S. 

 Fish Commission. This article, like most of the others, is ex- 

 cellently illustrated. They all help to disclose the possibilities 

 of fish industries in the United State?, and indicate how " the 

 harvest of the sea" may be increased in value. 



We have received a ponderous volume (vol. vi.) of the 

 transactions of the Reale Accademia delle Scienze Fisiche e 

 Mathematiche, Naples. The volume contains nineteen fine 

 plates and eighteen papers, most of which refer to natural 

 science subjects. 



Mr. Rowland Ward, the well-known taxidermist, has pub- 

 lished the seventh edition of his " Sportsman's Handbook," 

 containing information on the "practical collecting, preserving, 

 and artistic setting-up of trophies and specimens, to which is 

 added a synoptical guide to the hunting grounds of the world." 



The second volume of Priestley's " Experiments and 

 Observations on Different Kinds of Air" — that is to say, the 

 one in which he first gave an account of the discovery of oxygen 

 in 1775— is reproduced in the seventh number of the handy 

 "Alembic Club Reprints," published by Mr. W. F. Clay, 

 Edinburgh. The next volume in this series will contain 

 Scheele's work in connection with the discovery of oxygen. 



The Robert Boyle lecture, delivered by Lord Kelvin before 

 the Oxford University Junior Scientific Club, in .May last, on 

 "The Molecular Tactics of a Crystal," has been published by 

 the Clarendon Press. No student of crystallography should 

 neglect to read the lecture, for in it the geometry of crystalline 

 structure is dealt with in the simplest manner. The substance 

 of the lecture is contained in a paper read by Lord Kelvin 

 before the Royal Society on January l8, and reprinted in these 

 columns on March 8. 



Messrs. George Philip and Son have lately published a 

 book, of fifty pages, entitled "Knowledge through the Eye," 

 by Mr. .A.. P. Wire and Mr. G. Day. The authors explain how 

 to use the optical lantern in illustrating lectures in science and 

 other branches of knowledge, and describe anew method of pre- 

 paring lantern slides without the use of a camera. A drawing of 

 the required Illustration is first m'lde. A piece of specially pre- 

 pared transparent paper (sold by Messrs. Philip) is then placed 

 over it, and the drawing is transferred by tracing. A lantern 

 slide is obtained by making a contact exposure in the ordinary 

 manner, using the picture on the transparent paper as a negative. 

 This method, however, has very little to commend it. Line 

 drawings are easily made upon a plate of smoked or varnished 

 glass, or upon glass having a thin film of collodion upon it; and 

 as the illustrations have to be drawn in any case, it is just as well 

 to do the work directly as to make a lantern slide of a tracing 

 made from a drawing in the way described by the authors. 



The additions to the Zoological Society's Gardens during 

 the past week include a Hairy Armadillo {Dasypus villosus) 

 from South America, presented by Mr. George Simpson ; a 



Bamboo Rat (Klihomys, sp. inc.) from India, presented by 



Mr. Angus M. Kinloch ; a Himalayan Monaul {Lophophorus 



NO. 1296, VOL. 50] 



impeyanus) from the Himalaya^, presented by Captain H. R. H. 

 Helpman ; two Sharp-nosed Crocodiles {Crocodilus acutus) 

 from Jamaica, presented by Dr. Poole ; two Common 

 Chameleons (Chamcclion vulgaris) from North .'\frica, presented 

 by Mr. E. Palmer; two Smooth Snakes {Coronella lavis) from 

 Hampshire, presented by Mr. E. Penton ; two Common Vipers 

 ( Vipera bcrus], British, presented by Mr. Hugh Bromley ; a 

 Sykes's Monkey {Cercopithccus albigiilaris) from East Africa ; 

 two Heloderms [Hehderyna suspeclum) from Arizona, deposited ; 

 three Blood-breasted Pigeons (Phlogtrnas crueniata) from the 

 Philippine Islands, purchased ; a Yak (Paphagus grunniciis), 

 born in the Gardens. 



0(/R ASTRONOMICAL COLUMN. 



Solar Eclipse Photography. — -Mr. Albert Taylor recently 

 read a paper before the Royal Dublin Society, on the selection 

 of suitable instruments for photographing the solar corona 

 during total solar eclipses. The photographs obtained by other 

 observers and himself during the total eclipse of April 1893, 

 have indicated the best methods, both photographic and instru- 

 mental, to be adopted for the next observable total solar eclipse, 

 on August 8, 1896. One of the most disputed points in eclipse 

 photography, says Mr. Taylor, refers to the proper exposure 

 required to obtain the faint extensions of the corona without 

 fogging the plate by the sunlight. Two opposite opinions are 

 held as to the best method of photographing these diaphanous 

 coronal extensions. Short exposures and slight photographic 

 action are believed by some observers to give the best results, 

 but others hold that long exposures and great photographic 

 action are necessary to attain the desired end. An examination 

 of the photographs obtained during the eclipse of April 1893, 

 shows that the latter view must be abandoned ; and that nothing 

 is to be gained by using photographic actions exceeding 15 or 16. 



Photographic action is determined by the formula 100 — t. s., 



where a is the aperture of the instrument employed, /the focal 

 length, / the time of exposure, and s the sensitiveness of the 

 plate. For obtaining photographs showing the detailed struc- 

 ture of the inner and middle coron:e, short exposures and a 

 long-focus object-glass are recommended. The opinion is 

 expressed that, with a twelve-inch object-glass of between forty 

 and sixty feet focus, one hundred seconds' exposure would give 

 nearly all the corona that is within reach of the photographic 

 method of attack in the present state of photography. It is 

 believed that with an instrument having a focal length equal to 

 ten times the aperture, all the external corona would be 

 obtained in about fifteen or sixteen seconds. 



Observations of Saturn and Uranus. — Since the be- 

 ginning of this year Prof. E. E. Barnard has used the 

 36-inch of the Lick Observatory in some observations of 

 Saturn and Uranus {Astronomy ami Astro- Physics, .\ugust). 

 Measurements of the former planet were undertaken with 

 a view of determining whether the ball was situated in the 

 exact centre of the rings. Between the end of the ring 

 and the limb on the following side of Saturn the angular dis- 

 tance was II "■287, while similar measures on the preceding side 

 gave 1 1 "•167. The difference is less than one second of arc, and 

 It may very well be due to some peculiarity in the measures. It 

 is certainly not sufficient as yet to suggest that the planet is not 

 exactly at the centre of its rings. Prof. Barn.ard has also made 

 a series of measures of the polar and equatorial diameters of 

 Uranus, and a series of measures of the position angles of the 

 equator. From these it appears that "the equator of the planet 

 coincides with the planes of the orbits of the satellites, thus 

 verifying the supposition that Uranus rotates on an axis 

 deviating but little from the plane of its orbit." 



B TO LOG YAT THE BRl TISH ASS OCT A TION. 



gECTION D, in spite of the loss of Physiology, had so 

 many papers that it was necessary to meet on most 

 days under the two departments of Zoology and Botany. A 

 noteworthy feature was the large number of papers by 

 distinguished foreigners, and the theoretical nature of a large 

 proportion of the communications. 



