THE FARMERS' REGISTER. 



153 



in a refrisxerator is isolateil and protected Crom (he 

 surrouiuiin^ lemperature l>v llie bad conductint^ 

 sides oftlic relrigeralrtr. The Ice IMnuntain only 

 requires lor ilie ox|)ianalion of its plienomenon, 

 the application of the familiar principle npon 

 wliieii is cnnslrncted the comnion roCritrerator, 

 which, by the t)ad cotiductinir nature of its side*^, 

 temporarily ed'ects what the Ice JMounlain per- 

 manently does ; a (pmperature independent olall 

 exiernal causes. 'I'he Ice Mountain is in ("act a 

 hufje sandstone relriirerator, whose increased and 

 unusual effects beyond those of the ordinary re- 

 I'riiierator, arc due to the increased and unusual 

 collection of poor conducting materials, whicii 

 form its sides. 



Similar, ihoujjh in'erior, accumulations to that of 

 the Ice Mountain, lixm geolos^ical causes un- 

 necessary here to explain, frequently occur in 

 Hampshire, and the adjoininor counties. Obser- 

 vation in every instance showed them to, have a 

 temperature (ar below that of the surrounding at- 

 mosphere. That this low temperature is perma- 

 . pent, is proved by the universal custom of persons 

 residing in the vicinity of these accumulations, so 

 constructing their dairies that three of their sides 

 are enclosed by th^ rocks in the same manner as 

 the one already mentioned at the Ice Mountain. 

 Even a thin layer of poor conducting materials 

 affords a much greater protection than would be 

 anticipated by those whose attention had not' been 

 called to the subject. The means resorted to by 

 the shepherds of Mount Etna, for supplying their 

 flocks with water, exhibits the protecting influence 

 of a sliglit covering of bad conducting materials. 

 The shepherds, during the winter, cover the enow 

 with a layer of volcanic sand and ashes a few 

 inches in thickness, which perfectly protects it from 

 the sun, and preserves it throughout the fummrr, 

 thus affording them an abundant supply of water 

 for their flocks where it could be obtained from no 

 other source. 



A still more interesting and striking proof of 

 the perfect isolation from external causes, by a 

 poor conducting covering, is attested by the fact, 

 that a large glacier of ice and snow was over- 

 flowed by a stream of hot lava from Mount Etna, 

 without being destroyed.* The ire ihus covered 

 by the lava was protected by it from the sum- 

 mer's heat, and continues thus preserved to the 

 present day. This can only be explained by sup- 

 posing that the lower poriion of ihe lava current 

 immediately upon its contact with the ice, was re- 

 duced to liie temperature ol the glacier, and that 

 this reduced stratum, from its imperfect power of 

 conducting heat, protected the ice from the hot 

 lava above.! Whatever may be the explanation 

 of it, or however paradoxical it may appear, the 

 flict is attested by too high authorities to be 

 doubted. Public attention was first called to this 

 interesting fact in 1828, when the discovery was 

 made by Signor Gemmellaro, in searching afier 

 ice. It has been subsequently examined by Lyell 

 and other distinguished geologists, who confirm 

 the report of Signor Gemmellaro. Excavations 

 made for removing the ice, have exposed the lava 

 for several yards, overlying the glacier, and so su- 

 per-imposed, that the relative position of the lava 

 and glacier can only be accounted for by supposing 



that the latter was overflowed by the fjrmcr, in a 

 molten stale. Monte Testaceo may be instanced 

 ac= presenting a phencmienon more strictly parallel 

 with that of the Ice Mountain, and as aflbrdin"' 

 a happy illustration of the principle so fre(jucntly 

 alluded to. Monte Testac(«) is situated in one of 

 the suburban r/(wf ofKome. It is merely a large 

 mound, composed of fragments of earthenware 

 vases and urns, and is snp|)oeed to mark Ihe site 

 of an extensive ancient poller}-. _ This accumu- 

 lation of bad conducting materials preserves a 

 uni'orm leniperaiure, many degrees below the 

 mean temperature ol the climate, and on this ac- 

 count artificial cavities formed by digging in the 

 sides of the hill are used as wine vaults.* In 

 July, 1773, Prof. Pic.tei Ibund by observation the 

 temperature of one of the caves to he 44"^, while 

 that of Ihe external atmosphere v/as 78°. If 

 this comparatively small accumulation produces 

 tliis effect in Kome, where the mean temperature 

 is 60°, it can readily be conceived that the still 

 greater accumulation at the Ice Mountain, would 

 produce a similar but increased efl"ect in a climate 

 wliere mean temperature is but 51 or 52°. f 



In endeavoring to elucidate the phenomenon of 

 the Ice Mountain, the eflect resulting from the 

 bad conduciins power of the rocks has alone been 

 considered. Their nature as absorbents of heat 

 should also be estimated, as from their dull white 

 color most of the heat would be renec:ed, leavintr 

 but a small portion to be absorbed by the rocks! 

 It should also be borne in mind, that the air, im- 

 mediately in contact with the ice, would be, Irom 

 iis low temperature, specifically heavier than Ihe 

 exiernal atmosphere, except in midwinter, and 

 could only be replaced by atmosphere heavier than 

 iiself, wfiich would necessarily he colder. It hence 

 follows that the ice could only be allected by the 

 hot air of summer, so far as its heat is conducted 

 by the surrounding rocks, which, as will appear 

 liom the foregoing explanations, must be very in- 

 considerable. These remarks and the examples 

 adduced, will, it is presumed, suflicienily illustrate 

 the proposed explanation of Ihe low temperaUire 

 of the Ice Mouniain. Should this rxftlanation 

 prove unsatisfactory, it may at least serve to in- 

 vile attention to ^he sul'ject, and elicit a more sa- 

 tisliictory solution from abler sources. 



C. B. Hayden. 

 Smithfidd, March 1st, 1841. 



*Lyell's Geology, Volume 2nd, page 124. 

 t Lava, from its open vesicular texture, i 

 tremely bad conductor of heat. 



BIODES OF MEASURING GRAIN. 



To tlie Editor of tlie [''arnicrs' Register. 



i:disto Island, S. C, March 1st, 1841. 

 In the Southern Agriculturist of May, 1834, I 

 published a " rule for ascertaininir the quaniity of 

 shelled corn in a house of any given dimensions." 

 I perceive, in your last number, that this rule has 

 been referred to, by a wriicrin ihe Kentucky Farm- 

 er, Mr. John Lewis. He admits ihal it is simple, 

 and of easy application, but suggests that it can- 

 not be accurate in cases where a given measure 

 of corn in the ears, turns out, when shelled, less 

 or more than half of that measure. The gentle- 

 man is right ; the rule is derived from arithme- 

 tical principles, and, so far, is correct, but il ope- 



* Jameson's Philosophical Journal, 

 t Deduced from ob.sprvations on the temperature of 

 thi^ .spring.s. 



