522 



SCIENCE, 



[Vol. V., No. 125. 



unmistakably with the disturbance in the rocks 

 caused by their upheaval into arches, but the 

 crucial test was yet to be made in the actual 

 location of good gas territor}' on this theory. 

 During the last two 3'ears, I have submitted it 

 to all manner of tests, both in locating and 

 condemning gas territory^, and the general re- 

 sult has been to confirm the anticlinal theory 

 beyond a reasonable doubt. 



But while we can state with confidence that 

 all great gas- wells are found on the anticlinal 

 axes, the converse of this is not true ; viz., that 

 great gas-wells may be found on all anticlinals. 

 In a theory of this kind the limitations become 

 quite as important as, or even more so than, the 

 theory itself; and hence I have given consider- 

 able thought to this side of the question, hav- 

 ing formulated them into three or four general 

 rules (which include practically all the limita- 

 tions known to me, up to the present time, that 

 should be placed on the statement that large 

 gas-wells may be obtained on anticlinal folds) , 

 as follows : — 



(a) The arch in the rocks must be one of 

 considerable magnitude ; (6) A coarse or po- 

 rous sandstone of considerable thickness, or, 

 if a fine-grained rock, one that would have 

 extensive fissures, and thus in either case ren- 

 dered capable of acting as a reservoir for the 

 gas, must underlie the surface at a depth of 

 several hundred feet (five hundred to twenty- 

 five hundred feet) ; (c) Probably very few or 

 none of the grand arches along mountain ranges 

 will be found holding gas in large quantity, 

 since in such cases the disturbance of the strati- 

 fication has been so profound that all the nat- 

 ural gas generated in the past would long ago 

 have escaped into the air through fissures that 

 traverse all the beds. Another limitation might 

 possibly be added, which would confine the area 

 where great gas-flows may be obtained to those 

 underlaid by a considerable thickness of bitu- 

 minous shale. 



Very fair gas-wells may also be obtained for 

 a considerable distance down the slope from 

 the crest of the anticlinals, provided the dip be 

 sufficiently rapid, and especially if it be irregu- 

 lar, or interrupted with slight crumples. And 

 even in regions where there are no well-marked 

 anticlinals, if the dip be somewhat rapid and 

 irregular, rather large gas-wells may occasion- 

 ally be found, if all other conditions are favor- 

 able. 



The reason wlrv natural gas should collect 

 under the arches of the rocks is sufficiently 

 plain, from a consideration of its volatile na- 

 ture. Then, too, the extensive Assuring of 

 the rock, which appears necessary to form a 



capacious reservoir for a large gas-well, would 

 take place most readily along the anticlinals 

 where the tension in bending would be great- 

 est. 



The geological horizon that furnishes the best 

 gas-reservoir in western Pennsylvania seems 

 to be identical with the first Venango oil-sand, 

 and hence is one of the Catskill conglomerates. 

 This is the gas-rock at Murray sville, Taren- 

 tum, Washington, Wellsburg, and many other 

 points. Some large gas-wells have been ob- 

 tained in the subcarboniferous sandstone (Po- 

 cono) , however, and others down in the third 

 Venango oil-sand (Chemung) . 



In Ohio, gas-flows of considerable size have 

 been obtained deep down in the Cincinnati 

 limestone, while in West Virginia they have 

 been found in the Pottsville conglomerate : 

 hence natural gas, like oil, has a wide range 

 through the geological column, though it is a 

 significant fact that it is most abundant above 

 the black slates of the Devonian. 



Of the composition, probable origin, extent 

 of gas territory in the country, and many other 

 interesting points connected with natural gas, 

 the necessary brevity of this article forbids any 

 mention ; but the writer has in preparation a 

 more general paper on the subject, in which 

 these and kindred questions will be discussed 

 with more detail. I. C. White. 



THE EFFECTS OF COLD ON LIVING 

 ORGANISMS. 



Mr. Coleman and Professor McKendrick have 

 made some remarkable experiments 1 on the effect of 

 low temperatures on living organisms, particularly 

 microbes, using for this purpose the cold-air ma- 

 chinery invented by Mr. Coleman, which, in its ordi- 

 nary working, delivers streams of air cooled to about 

 80° below zero (—63° C), but by certain modifica- 

 tions as low temperatures can be secured as have yet 

 been produced in physical researches. The actual 

 temperatures in these experiments were taken by an 

 absolute alcohol thermometer, made by Negretti and 

 Zambra, and checked by a special air thermometer 

 devised by Mr. Coleman. 



The experiments consisted in exposing for hours 

 to low temperatures putrescible substances in her- 

 metically sealed tins or bottles, or in flasks plugged 

 with cotton wool. The tins or flasks were then 

 allowed to thaw, and were kept in a warm room, the 

 mean temperature of which was about 80° F. They 

 were then opened, and the contents submitted to mi- 

 croscopical examination. The general result may be 

 stated thus: The vitality of micro-organisms cannot 

 be destroyed by prolonged exposure to extreme cold. 

 It is clear, therefore, that any hope of preserving 

 meat by permanently sterilizing it by cold must be 

 1 Proc. Philos. soc. Glasgow, March 4, 1885. 



