192 



SCIENCE. 



[N. S. Vol. XI. No. 266. 



Of Dr. Buckley's explanation, p. 383, of the 

 unfavorable action of freezing temperatures, 

 Mr. Merrill says there is ' an unconvincing air 

 of freshness.' For my own part, I think Dr. 

 Buckley is correct In his explanation of the re- 

 sistance which many porous rocks, like sand- 

 stones, exhibit to alternate freezing and thawing, 

 while other rocks which may contain no more 

 than one per cent, of pore space suffer severely 

 under such conditions. This matter cannot be 

 fully expounded in this review, but Dr. Buck- 

 ley's explanation in brief is that in rocks in 

 which the pore spaces are large and connected, 

 the water is drawn off or distributed by capil- 

 larity, leaving the pore space only partly filled 

 by water. When this water freezes there is 

 room for expansion within the pores without 

 rupturing the rocks. On the other hand, in 

 some rocks in which the pore spaces are very 

 small and discontinuous, the pores remain en- 

 tirely filled by water, and when they freeze the 

 expansion ruptures the rock (pp. 20-25, 374- 

 375). Dr. Buckley's conclusion is fully war- 

 ranted by his experiments, which show that 

 fine-grained, compact limestones and granites 

 which have a very small pore space, often lose 

 more in strength by freezing and thawing than 

 do the sandstones having a large percentage of 

 pore space. I am not aware that experi- 

 ments have before been made which show the 

 actual effect of freezing and thawing on the 

 strength of the rocks. Nor have experiments 

 shown the relation of the size of the pores to 

 the diminution in strength due to freezing and 

 thawing, and Dr. Buckley's results on this 

 point are believed to have economic value. 

 However, whether this be so or not, they have 

 a scientific value bearing on the disintegration 

 of rocks in the belt of weathering. 



Another matter discussed, upon which Dr. 

 Buckley has made a contribution of general 

 value to the science of geology, is the more ac- 

 curate determination than has heretofore been 

 done of the pore space of rocks. Tolerably 

 well indurated sandstones he finds to vary in 

 pore space from 10 to 20 per cent., or more, and 

 in one case, that of the Dunnville sandstone, 

 the pore space is over 28 per cent. (pp. 402- 

 403). These results are of great importance as 

 showing the actual amount of material which 



must be added by underground waters in order 

 to completely cement a rock. From Dr. Buck- 

 ley's results it is a safe inference that in the 

 cementation of clean sandstones to quartzites, 

 there must have been contributed by under- 

 ground waters at least one-quarter of the entire 

 volume of the rocks. In determining the pore 

 space of building stones, their specific gravities 

 have also been obtained by a method more ac- 

 curate than has heretofore been used. 



Dr. Buckley's observations on joints in the 

 State of Wisconsin (pp. 458-459, PI. 49) have 

 an important bearing upon structural geology. 

 These observations are shown upon the map 

 and indicate that the dominant joints of the 

 sedimentary rocks of Wisconsin are in nearly 

 vertical position and in two sets nearly at right 

 angles to each other, trending NW-SE and 

 NE-SW. The position of these joint systems 

 with reference to the folding has an important 

 bearing upon theoretical structural geology 

 which cannot here be discussed. In connec- 

 tion with certain structural work of my own I 

 have searched for such information in many 

 volumes, but nowhere else have I found a set 

 of observations upon joints over so wide an 

 area. 



In conclusion it seems to me that the size of 

 Dr. Buckley's book is justified by the necessity of 

 putting in a State report the information which 

 the people of the State wish. It seems to me 

 further that the report differs from a number of 

 previous State reports in containing consider- 

 able material which is of general value to 

 geology. C. R. Van Hise. 



HYDROSTATIC VS. LITHOPIESTIC THEORY OF 

 GAS V7ELL PRESSURE. 



The paper read at the Orton Memorial Meet- 

 ing at Columbus, entitled ' Edward Orton Geol- 

 ogist,' and published in Science, January 5th, 

 contains a reference to Professor Orton's theory 

 of nature of gas and water pressure in gas 

 wells that calls for some comment. 



The writer has for some time not been entirely 

 satisfied with the ' Hydrostatic Theory of Gas 

 Pressure.' He noticed that Professor Orton, 

 himself, a short time before he died, expressed 

 himself in a way as to indicate he was not alto- 

 gether satisfied with his own theory. 



