10 



PROt'KHI)IN(!S or I llK 



It was slatttl thai thr mumm tt ii»iK'ra(iiro of \H^7, was •iS.T'i 

 Fahr. while ihv mvixn of 1() prccodini:; years, as ri'<;isUTi'(l at the 

 Gnrtlon was r»(>"(;\i, and tonsiMnu'ntly ihv year I8:i7 was ahont 2" 

 roldrr than ii<ual. notwitlistaiuliiig the al)sen(r of severe weather 

 in January, and the e\tra(»r(linary mildness of December. 'I'hc 

 lowness of len)|)eratu!e ocenrreil in tlie jz^rowinfi; part of the 

 pcason, and more especially in March, April, and May. The 

 season was not only colder hnt much drier: for the whole amount 

 of rain was only 1!>.HS inches, w hicli is ahont 1 inches below the 

 nverai^c (piantity that falls round London. 



Mr. 'rhoin])son communicated a memorandum conccrninc; the 

 temperature of the earth for the 7 bi^t months of \HS7 ; as indi- 

 cated by two (ieolhermometcrs buried in the soil, one a foot, and 

 the other '2 feet below the surface, and c()mi)ared with a com- 

 mon thermometer snsi)endcd in the air 3 feet above them. 



The monthly results are expressed in the following table. 



1 



Mean Temperature of earth 

 iiulicMted i)y the two 

 (icoiherniometcrs. 



Mean Temperature of air 

 indicated hy a common 

 Thermometer 3 feet above 

 ground. 



June 



59.01 



60.08 



J Illy 



64.19 



63.16 



Auiiu^t 



63.38 



62.53 



Srpternher 



57.92 



55.68 



Octoher 



53.60 



50.00 



N'oveinher 



44.62 



40.22 



Decp.ml)er 



42 74 



41.38 



Mean 



1 55.06 



1 53.29 



P>om the above, it appears that the difference between the ter- 

 restrial temperature at the above depths, (1 and 2 feet), and that 

 of the atmosphere near the surface of the earth, is Ij^-^ Fahr. But 

 as the ground is comparatively warmer than the almospbere in 

 the autumn, and colder in spring, it may be inferred that the 

 mean temperature of the earth, a little below the surface, agrees 

 very closely with that of the atmosphere, taking the average of 

 the whole year into account. 



The average of the I foot Geothermometer was 55^.01 

 of the 2 feet do. was 55M3 



The difference being only about ~ of a degree. 



The highest temperature indicated by the 1 foot Geothermo- 

 meter, was 60^ and by the 2 feet instrument 6'6°. This occurred 

 about the 2Sth of July • but on the whole, July and August 

 maintained nearly an equal terrestrial temperature. The diffe- 

 rence between these months and December, was upwards of 20'^. 



