382 Scientific Intelligence. 



teacher, or reader and a valuable compendium for practical work. 

 The typography is most satisfying and the illustrations beauti- 

 fully done. Their number has been increased from 228 to 240 in 

 this edition. As a work on general astronomy it is unequalled in 

 any language and on account of the present state of exchange its 

 cost is but a fraction of what would be required to produce it in 

 any other country. F. E. b. 



7. The Two Orbit Theory of Radiation; by Frank H. Bige- 

 low. Pp. VII, 37. Vienna 1921 (Austrian State Printing 

 Office). — This brochure is designated as Supplement No. 2 to 

 Treatises on the Atmospheres of the Sun and the Earth. For 

 the purposes of atmospheric physics the author rejects the Bohr 

 theory of stationary non-radiating orbits with electrons jumping 

 across radial differences with a frequency v, as too artificial for 

 general application. In its place he proposes a two orbit theory 

 of radiation in which it is assumed that the negative electron is 

 revolving about the positively charged atomic nucleus while the 

 latter is revolving about the instantaneous line of translation. 

 Under these conditions the velocity of the electron is periodically 

 variable and generates trains of radiation. 



The paper attempts to show by thermodynamic reasoning the 

 origin of solar radiation and the location in the solar atmosphere 

 where the several spectrum lines originate. f. e. b. 



II. Geology and Mineralogy. 



1. TJeber das Becken, den Schidtergurtel und einige andere 

 Teile der Londoner Archaeopteryx, by Branislav Petronievics. 

 Pp. 31, 2 pis., Genf (Georg & Co.), 1921.— These studies are the 

 result of further preparation of the famous British Museum 

 specimen of Archceopteryx which has exposed a number of new 

 skeletal elements. A description and dimensions are given of 

 the pelvis, and it is compared with that of the. Berlin specimen 

 and with that of other birds and reptiles. The shoulder girdle 

 and other elements are treated in the same manner. As a result 

 of these comparisons, the author arrives at the following con- 

 clusions : (1) that the birds are undoubtedly derived from the 

 reptilian stem; (2) that their ancestors are to be sought among 

 the Lacertilia, or that at least birds and Lacertilia came from a 

 common ancestry; (3) that the similarities between the birds on 

 the one hand and the Dinosauria and Pterosauria on the other 

 are due to convergence ; (4) that Archceopteryx both in its pelvic 

 and shoulder girdles is more primitive than Archceomis; (5) 

 that Archceopteryx represents a generalized as well as a mixed 

 bird-type, since it combines primitive reptilian characters with, 

 advanced bird characters; (6) that Archceopteryx either stands 

 near that generalized bird-type out of which developed both the 

 modern Carinates and Ratites, or is itself that type; (7) that as 



