660 



SCIENCE 



[N. S. Vol. XXIX. No. 747 



pressed them with such speed." Neither Mr. 

 Lowell nor any one else knows whether the 

 vegetation in the Carboniferous swamps grew 

 slowly or rapidly. We know only that they 

 produced a certain; body of coal. That may 

 have taken a short time at a rapid rate, or a 

 long time at the slow rate; the results would 

 be the same. As to the warmth, it may be 

 remarked that coal seams are now in process 

 of growth in Alaska and Labrador and that 

 many of the Carboniferous plants show by 

 their structures an adaptation to severe rather 

 than genial climatic conditions. Only a 

 little later than the Carboniferous period most 

 of the lands adjacent to the Indian Ocean ex- 

 perienced a glacial period, comparable to that 

 of recent times in Canada; and in Australia 

 the coal seams are interbedded with layers of 

 glacial drift. Does this bespeak a torrid 

 climate in middle latitudes at that time? 

 Even the moist conditions seem to have been, 

 as now, of local prevalence only, for aridity is 

 indicated by the Carboniferous red beds' and 

 gypsum of Colorado and some other regions. 



One of the terrestrial conditions which Mr. 

 Lowell finds it necessary to postulate in order 

 to bolster up his theory of Martian evolution, 

 is a perpetual cloud envelope around the earth 

 down to about Mesozoic times — "a shady 

 half-light " which he says is attested " by the 

 habit of the ferns' of to-day." That tree- 

 ferns now stand out isolated on the brushy 

 hills of equatorial Africa under the blazing 

 tropical sun is evidently unknown to the au- 

 thor. Under the circumstances he would 

 have found the services of a botanist advan- 

 tageous. 



With the hypothesis of a perpetually damp 

 cloudy atmosphere we can hardly reconcile 

 the existence of deserts in India in the Cam- 

 brian, in New York in the Silurian, in Michi- 

 gan and New Brunswick in the Carboniferous, 

 and in Germany in the Permian period. Yet 

 the testimony of the rocks is emphatic that 

 they did exist in those times and places. 



Another of the author's preconceived opin- 

 ions of Mars, which the history of our own 

 planet has been twisted and squeezed to fit, is 

 the shrinkage of the oceans and the eventual 

 disappearance of water in any form. Ac- 



cording to Mr. Lowell, Mars had oceans but 

 lost them, and the earth is merely in an 

 earlier stage of the same process. As to the 

 earth, he says, " observation proves this to be 

 a fact," and goes on to cite Professor Dana, 

 who many years ago propounded the opinion 

 that the lands had grown steadily larger from 

 smaU. beginnings. If Dana were alive to-day 

 he would doubtless repudiate the idea, for it 

 is wholly contrary to the mass of facts more 

 recently made known. If Lowell were right, 

 land on the continent of North America would 

 have been smallest in the Archean and be 

 greatest now. The truth is that there have 

 been fluctuations of land and sea throughout 

 recorded geologic history, and these changes 

 show no general tendency. Just before the 

 Cambrian period the continent was nearly aU 

 out of water; at the close of that period it 

 was at least half submerged. At the close of 

 the Permian it emerged more extensively than 

 ever and yet in the Cretaceous it was again 

 deeply inundated. Examples of the same 

 thing could be largely multiplied, but are too 

 well known to make that necessary. 



In the face of aU these facts Mr. Lowell 

 coolly states that " wherever geologists' have 

 studied them, the strata tell the same tale," 

 viz., the land has spread, the ocean shrunk. . . . 

 No competent geologist would admit a word 

 of this. Yet on this comfortable basis of 

 fallacy Mr. Lowell then proceeds " Now, a 

 general universal gain of the sort can mean 

 only . . ." One is tempted to direct the au- 

 thor's attention to his own preface wherein he 

 seriously admonishes that " the cogency of the 

 conclusion hangs upon the validity of each 

 step in the argument." The reader can 

 judge for himself of the cogency of this par- 

 ticular conclusion. 



Having assured his readers that the earth 

 is drying up and that it wiU sooner or later 

 " roll a parched orb through space," he cites 

 as proof the alleged fact that deserts are in- 

 creasing in size. This is the beginning of 

 the dreadful end which " is as fatalistically 

 sure as that to-morrow's sun will rise, unless 

 some other catastrophe anticipate the end." 

 Here again the proverb applies, " a little 

 knowledge is a dangerous thing." Mr. Lowell 



