March 25, 1920] 



NATURE 



117 



Our Astronomical Column. 



The Total Solar Eclipse of 1918 June 8. — 

 Vol. Iviii., No. 4, of the Proceedings of the American 

 Philosophical Society is entirely taken up with a dis- 

 cussion of the observations made during this eclipse. 

 The photographs taken by the Lowell Observatory 

 Expedition at Syracuse, Kansas, bring out very clearly 

 the connection between the prominences and the 

 coronal arches. It is pointed out that this connection 

 is much easier to trace at sun-spot maximum than at 

 minimum. Dr. Slipher's photographs of the coronal 

 spectrurh indicate that coronium is much more abun- 

 lant in the equatorial than in the polar regions. 

 Messrs. Jakob Kunz and Joel Stebbins were stationed 

 at Rock Springs, Wyoming, and measured the total 

 light of the corona by photo-electric cells. Compari- 

 son was made with the full moon through the inter- 

 mediary of standard candles. Allowing for absorption 

 bv the atmosphere, the total light of the corona was 

 I 07 candle-metres, just half the value found for the 

 full moon. Comparison of the corona with the sky 

 near the sun before and during the eclipse showed that 

 the corona gave i/ioth of the sky light (same area) 

 in full sunshine, and six hundred times the sky light 

 during totality. It is obvious that most of the illu- 

 mination of the landscape during totality comes, not- 

 from the corona, but from the distant regions of the 

 terrestrial atmosphere, which are outside the shadow. 

 Endeavours are being made by Prof. Hale at Mount 

 Wilson to detect the corona in daylight by the use of 

 photo-electric cells. 



Mr. John A. Miller, of the Sproul Observatory, 

 describes some researches to detect motion in coronal 

 streamers by comparing plates taken at different 

 stations. Recessions from the sun of 90, 60, and 

 15 miles per second were indicated for three different 

 streamers. Mr. Miller also states that the forms of 

 many of the streamers can be explained on the sup- 

 position that they are projected matter acted on by a 

 repulsive force. 



A Noon Reflector.— Prof. C. V. Boys describes 

 in the English Mechanic for March 5 an ingenious 

 little instrument which he states to be capable of 

 determining apparent solar time v^ithin a second. 

 It is essentially a transit instrument; a small mirror, 

 I in. in diameter, is mounted on an axis about 2 in. 

 long, with cylindrical ends v^/hich rest in two Y's, 

 mounted on a stand which is capable of being firmly 

 fixed in a window of southern aspect. Full details 

 and drawings of the various parts are given in the 

 article, with instructions which should enable any 

 person with a mechanical bent to construct it. Small 

 movements for fine adjustment in level and azimuth 

 are allowed for in the design. Some protecting cover 

 and some means of fixing firmly after adjustment is 

 secured are also demanded, as it is somewhat tedious 

 and troublesome to adjust it with high accuracy. The 

 mirror is so small that the reflection of the sun on 

 the opposite wall is fairly well defined, like a pinhole 

 image, and the author states that he has frequently 

 been able to see large sun-spots clearly. There is a 

 certain amount of penumbra, but bv practising uni- 

 formity in observing either the inside or the outside 

 of the penumbral fringe the time of transit of the 

 sun's centre may be determined to a second. The 

 meridian is marked by a line on the north wall of the 

 room ; the noon image of the sun may be brought to 

 the same point at all times of the year by rotating 

 the mirror axis in the Y's. 



NO '>f\2n vnr mil 



American Fossil Vertebrate Animals. 



A MERICAN palaeontologists are making good pro- 

 -^*- gress with their detailed studies and descriptions 

 of the original type-specimens of the various species 

 of extinct vertebrate animals found on their con- 

 tinent. Most of the first descriptions were necessarily 

 hurried and superficial, often Unaccompanied with 

 figures, and they are scattered in numerous small 

 publications. Later discoveries have indicated more 

 clearly the features that are of special significance 

 and need particular attention in each case, so that 

 new descriptions are of fundamental importance for 

 exactitude in the science. Realising this, Prof. H. F. 

 Osborn has just completed a valuable work by bring- 

 ing together a series of up-to-date technical descrip- 

 tions and figures of all the type-specimens of fossil' 

 horses from the Oligocene, Miocene, and Pliocene 

 formations of North America (Memoirs of the Ameri- 

 can Museum of Natural History, new series, vol. ii., 

 part i.). He not only deals with every species on a 

 uniform plan, but also discusses in ample detail the 

 correlation of the various formations from which the 

 fossils were obtained. Besides reproducing the 

 original figures already published, he adds many 

 more, and among these the pencil drawings by two' 

 Japanese artists are especially noteworthy. A series 

 of new drawings collected to illustrate the evolution 

 of the upper and lower molars of the horses is a 

 welcome compendium. 



Other fossil mammals are described and discussed 

 in the sixth volume of papers on vertebrate palaeonto- 

 logy extracted from the Bulletin of the American 

 Museum of Natural History, 1915-17. We noticed 

 some of these contributions at the time of 

 their publication, and we are glad to have them 

 so conveniently collected. Several notes on the 

 mammalian remains of the Lower Eocene by Messrs. 

 W. D. Matthew and W. Granger add to our know- 

 ledge of the type-specimens by comparison with later 

 discoveries, which are described and illustrated in 

 detail. The paper on the Eocene Notharctus by 

 Messrs. W. Granger and W. K. Gregory is also 

 fundamentally important for a discussion of the origin 

 of the Primates. In another valuable memoir Dr. 

 Gregory pursues this subject, and reviews our present 

 knowledge of the fragmentary fossils which seem to 

 afford some information as to the origin of man. 



The skeleton of Dintryma. a heavy running bird 

 7 ft. high, from the Lower Eocene of Wyoming, is 

 described by Messrs. Matthew and Granger as repre- 

 senting a new order of uncertain relationships. Some 

 of the Cretaceous Dinosaurs described bv Prof. 

 Osborn are also remarkably bird-like; and the won- 

 derfully preserved Corythosaurus described bv Mr. B. 

 Brown, though evidently an amphibious Dinosaur 

 related to Iguanodon, has a bony crest which would 

 make the outward shape of its head like that of a 

 cassowary. 



In the volume from the .American Museum there 

 are also some notes on the gigantic Dinosaurs related 

 to Diplodocus. but a still more important contribution 

 to our knowledge of these reptiles is Prof. R. S. Lull's 

 detailed description of Barosaurus in the Memoirs of 

 the Connecticut Academy (vol. vi., pp. 1-42, pis. i.- 

 vit.). Barosaurus seems to have a longer neck and 

 snorter tail than Diplodocus, but is otherwise very 

 similar to the latter. The gigantic Sauropoda, 

 indeed, are not easily classified, and we still need 

 many mom technical descrintions like that before us. 



.Some of the type-specimens of the Permian and 

 Triassic reptiles are also redescribed and discussed by 

 Baron von Huene and Mr. D. M. S. Watson in the 

 Bulletin of the American Museum ; but the most 



