§0 



SCIENCE. 



m = 14, Si. Cu. Cd. and one of Mendelejeffs 

 hypothetical ones. 



m = 15 only Antimony, 120. 

 m = 16 S. Te. Hg. 

 m = 17 Se. Ce. 

 m — 20 Ca. Zr. 



It must be remembered that with this large value for 

 m, only three or four calculations are possible without 

 obtaining numbers quite beyond any known atomic 

 weights ; for instance, when m = 20, only three calcu- 

 lations can be made, two of which are atomic weights. 



With 66 serial computations, 49 elements are de- 

 termined ; 74 per cent, and more than that if Men- 

 delejeffs hypothetical elements may be counted. 



If there be any underlying truth in this theory of 

 calculation, then the conception of the elements will 

 be much simplified, for it will dispense at once with 

 complexity in the atom, and substitute a common 

 form for all, differing arithmetically from each other in 

 size and velocity. The only conception I have of the 

 term m corresponding to mass, is a relative volume of 

 ether in rotation with certain velocity. 

 Tufts College, Mass. A. E. Dolbear. 



RECENT ADDITIONS' TO THE E. M. MUSEUM 

 AT PRINCETON COLLEGE. 



Henry F. Osborn, S. D. 



The E. M. Museum of Geology at Princeton has re- 

 cently purchased Messrs. Ward & Howell's well-known 

 collection of fossil animals and plants. Under the partial 

 supervision of these gentlemen the collection has been un- 

 packed and hastily arranged in the cases, and as it has 

 never been fully displayed before, it now appears to very 

 great advantage and possesses peculiar interest. The 

 east wing of the museum already contains the collections 

 made by the Princeton western parties during the 

 summers of 1 877 and '78. These include several hundred 

 specimens of fossil insects preserved in the delicate Mio- 

 cene shales of Florissant, Colorado, and leaves from the 

 same neighborhood. The former have already passed into 

 the hands of Dr. Scudder for identification. Still more 

 valuable is a large collection of fossil leaves from Strata 

 closely overlying the Lower Eocene Lignitic Beds, near 

 Black Butte, Wy. Terr. These have been studied by Dr. 

 Lesquereux ; he pronounces them of great novelty as 

 contributing largely to our knowledge of the extent of 

 the Eocene Flora, and they will form the subject of a 

 special memoir to be published by the museum. 



Among the western Vertebrate collections are nearly 

 complete skeletons of various members of the Dino- 

 cerata family, parts of which have been figured and 

 described in bulletins from the museum. These, together 

 with numerous specimens of Palcrosyops and allied 

 genera, from the now classical beds of the Henry's Fork 

 and Bitter Creek country, Wy. Terr., together with a 

 great variety of carnivorous, rodent, lemurine and perhaps 

 insectivorous forms, many of which are undescribed, give 

 an admirable idea of the fauna inhabiting the Lower 

 Eocene. In addition to these are many complete turtles 

 and remains of lizards, snakes and birds. Representing 

 the Miocene is a collection Irom Colorado including widely 

 different forms. Prof. Cope, who has kindly glanced 

 over the whole collection, pencil in hand, pronounces 

 several of these forms new to science. 



The Ward collection is, however, of much greater value 



to the general student, as it includes representative speci- 

 mens from almost every age and country — from the dis- 

 puted Eosoon canadense of the Laurentian to the Post Plio- 

 cene cave bear and Irish elk. It is the result of seventeen 

 years of intelligent travel, purchase and selections. 

 Mr. Ward's theory being to perfect the collec- 

 tion by constantly substituting the best obtainable ex- 

 amples of each type, not aiming at a complete series for 

 each age, but giving a synoptic view from the dawn of 

 life upwards. In this he has succeeded, we have little 

 doubt, far beyond his own expectations at the outset, and 

 although his catalogues have made this collection familiar 

 to many palaeontologists in this country, it well deserves a 

 brief description here. 



The Silurian corals, crinoids and trilobites fill the first 

 cases. The latter are very fine. Among them is the out- 

 line of an Asaphus gigas indicating an animal over 12 

 inches long. On large stone slabs are other Crustacea, 

 Eurypterus and Pterygotus. These are the earliest of a 

 series represented in the Jurassic by a fine collection from 

 the Solenhofen Beds and throughout by numerous Trilo- 

 bites. The Solenhofen Crustacea include, among otheis, 

 Peneus, Glyphea, Eryon, Limulus, /Eger, and a very 

 perfect Megachirus, while from the English chalk are 

 some fine fossil crabs, Enoploclytea, Hoploparia, etc. 



The remains of Devonian Ganoids are very numerous ; 

 Osteolepis, Cheirolepis, Ptcricthys, Ceplialaspis and other 

 genera characteristic of the middle and lower Devonian. 

 Most interesting, however, is a fine block containing a 

 number of Holoptychii from the old red sandstone, 

 which specimen comes direct from Hugh Millers's col- 

 lection. From the Lias beds of Lyme Regis are well pre- 

 served specimens of Dapedius, Lepidotus, Eugnathus and 

 others varying in length from one to three feet. There 

 are fish remains from each epoch. The Solenhofen beds 

 have furnished a very beautiful group, including Cakuras, 

 Lepidotus, Leptolepis, Aspidorhynchus and others, im- 

 bedded in a clear yellow shale. 



There are fine examples of Lepidodendron and Sigil- 

 laria from the English, Prussian and American coal 

 measures ; also, many ferns. Among these are perfect 

 remains of Sphenopteris and Pecopteris from the Scottish 

 coal measures, with a full series from Mazon Creek, Illi- 

 nois. The fossil flora throughout is numerous, with 

 good collections from the German, Italian and French 

 Tertiary deposits. 



From the Jurassic are eleven entire Saurians marked 

 for their exceptional beauty, rather than great size. An 

 Icthyosaur, over 1 1 feet in length, is the largest of a 

 number of skeletons of this genus, and is finely preserved. 

 One complete skeleton and several parts give a very cor- 

 rect idea of Plesiosaurus. A head of Mistriosaurus 

 complete, rare in this country. From the Wurtemburg 

 Lias is a large Teleosaur with the ventral scales in posi- 

 tion. There is also a humerus of Pliosaurus. Besides 

 these are many fragments; the ossified Sclerotic of Icthy- 

 osaurus and parts of the neck, pelvic and shoulder girdles 

 affording a complete study. Probably belonging to the 

 saurians, too, are the so-called bird tracks from theTriassic 

 sandstone of the Connecticut River Valley, including 

 tracks assigned to Brontozoum, Anisopus and other 

 genera. Also of the five-toed Cheirotherium, supposed 

 to mark the steps of Labyrinthodon. 



The Echinoderms can be studied almost without inter- 

 ruption. In the earlier crinoid series are Periechocrinus 

 and Pentacrinus from the older strata. The latter are 

 represented beautifully and in profusion from the Lyme 

 Regis locality, England. Among later forms are Apio- 

 crtnusanA Eucrinus Lilliiformis, a rare specimen from the 

 Brunswick Muschelkalk. In the Echinoid series are per- 

 fect specimens of Periaster, Holaster and Hemiaster, in 

 addition to many others. Beautiful specimens of Asterias 

 and Astropecten and Ophiordcrma from the English Lias 

 represent in part the Star Fishes. 



The Cephalopods are a great feature of the collection, 



