Book Notices. 153 
year at Brussells—(=10°5 C. or 50°54 F.). The plane of 24 French 
feet is therefore a little above the depth at which the exact mean of the 
year would occur. The minimum temperature at this depth occurs in 
June and the maximum in December, while the surface extremes are at 
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of Mr. Quetelet’s observations would bring out these relations of tem- 
perature and depth, at the different parts of the year, beautifully. The 
epth at which the annual variations of temperature disappear, varies 
considerably, not only with latitude but with changes in the nature of 
the soil and rocks in the same place. Thus this depth is found at 
Zurich at 83-7 French feet; Strasburg at 81°6 ft.; Heidelberg in com- 
tion must be inappreciable.' 
Mr. Quetelet’s views of the constitution of the atmosphere differ from 
e 
supposes however that it is only the lower portion of the atmosphere 
strata 
the order of their specific gravities. He supposes that the cirri, the 
*% they approach the lower part of the selcsiiglietp, 0 if they ent 
*medium which had not the elements necessary for their continued 
lancy, 
brill 
Quetelet’s observations were undertaken originally with a view to confirm 
entally the well known laws of Fourier on this subject first promulgated in 
Moir, * Su 8 monuvements é 8 corps solides,” in Mem. de I Inst., 
the V. It is remarkable that the observations of Quetelet bave per confirmed 
mathematics usion of Fourier in every essen icular. 
AM. Jour, Sct.—Srconp Series, Vou. XXXV, No. 103.—Jax., 1863, 
20 
* Mr. 
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