March 6, 1908] 



SCIENCE. 



393 



fact that inherent earth-heat has always been 

 and will continue to be a controlling factor in 

 terrestrial phenomena, Hansen's hypothesis as 

 to the cause of the ice age may now, perhaps, 

 be said to be demonstrated as a true theory. 



Astronomical observations, for absolute 

 parallax of the fixed stars, when made from 

 the surface of a heat-radiating body revolving 

 about another central heat-radiating body, are 

 so influenced as to cause the stars to appear to 

 be more distant than they really are. The 

 effect is similar to the case which I have 

 already treated in No. 3935 of the Astrono- 

 mische Nachrichten, issued March 19, 1904. 



As will be demonstrated later on, the evi- 

 dence seems to be almost conclusive that our 

 now reduced sun is the parent body of both 

 the sidereal and the solar systems ; the former 

 created by one process simultaneously going 

 on with the creation of the latter by a largely 

 different action of the same forces of nature. 



J. M. SCHAEBERLE 



Ann Aebok, 



December 25, 1907 



PROGEESSUS REI BOTANIC^ 



It may not be amiss to call the attention 

 of botanical workers to the very excellent 

 summary of the present status of paleobotany 

 from the pens of Professors Scott, Zeiller and 

 Laurent which is contained in the first two 

 volumes of the " Progressus Eei Botanicse " 

 published by the International Association of 

 Botanists under the supervision of Dr. J. P. 

 Lotsy, of Leiden. 



There will no longer be any excuse for the 

 lamentable ignorance, too often displayed by 

 botanists, of the striking contributions of 

 paleobotany to the progress of botany. 



Professor Scott's article, the first to appear 

 and the most extensive, is entitled " The 

 Present Position of Palseozoic Botany," ' and 

 briefly discusses the great plant groups of the 

 Paleozoic, chiefly from the viewpoint of mor- 

 phology and phylogeny. The quickened in- 

 terest caused by the recent discoveries of seed- 

 bearing among the fern-like plants and the 

 actual proof of the fern ancestry of at least 



' Erster Band, erstes heft. 



the cycads among the gymnosperms will serve, 

 no doubt, to save this paper from neglect. 



The second article, by Professor Laurent, of 

 Marseilles, is entitled " Les Progres de la 

 Paleobotanique Angiospermique dans le der- 

 nier decade," " and may be said to treat of the 

 botany of the Cenozoic age, since the floral 

 Cenozoic commences with the dominance of 

 angiospenns in the Mid-Cretaeeous. This 

 paper, while it leaves much to be desired, is a 

 thoroughly good, if somewhat philosophical, 

 discussion of angiospermous fossils. It does 

 not go into details as much as would have 

 been desirable and treats of principles rather 

 than the available facts. 



The third article, which has just appeared, 

 is entitled " Les Progres de la Paleobotanique 

 de I'ere des Gymnospermes," ^ thus roughly 

 corresponding to the Mesozoic age and filling 

 the gap between the contributions of Pro- 

 fessors Scott and Laurent. This is a most 

 excellent summary of the recent progress in 

 the realm of Mesozoic botany and no dis- 

 covery however small seems to have escaped 

 Professor Zeiller's watchful interest. As this 

 treats of the age when cycads and ginkgoes 

 were dominant groups with a world-wide range 

 and when the ancestors of our modern conifers 

 and ferns make their appearance, it is one of 

 very vital interest. Naturally the recent work 

 of Wieland on the Bennettitaeea receives con- 

 siderable attention. 



A regrettable feature, seemingly part of the 

 plan of the editors, is the absence of citations, 

 except as to authors' names, and the lack of 

 any sort of bibliographies. Wiile this is ren- 

 dered unnecessary in the first instance by the 

 Paleozoic bibliography compiled by Professor 

 Arber and printed immediately following Pro- 

 fessor Scott's paper, it is greatly missed in 

 the other two papers. Paleobotanical workers 

 may be expected to be familiar with the litera- 

 ture, but this is hardly the case with the rank 

 and file of botanical workers to whom these 

 articles are primarily addressed. 



It is certainly a cause for congratulation 

 and a distinct sign of progress that the Inter- 

 national Association of Botanists recognizes 



^ Erster Band, zweites heft. 

 ° Zweiter Band, erstes heft. 



