34G 



0)i Hypsometrical Measurements. 



[No. 4. 



Now, in order to determine whether the hypothesis is correct or 

 not, it is only necessary to discover whether or not the quantity n, 

 as derived from observations made at different altitudes is coustant. 

 In the following table I have collected a few observations made by 

 Professor Forbes,* Dr. Hooker,f M. Marie,J and others, tabulating 

 in column (5) the value of n derived from each, and in column (6) 

 the boiling point corresponding to the observed pressures given in 

 column (3) calculated on the supposition that n = 112. Column 

 (7) shews the differences between these and the observed values. 



(1) 



(2) 



(3) 



(4) 



. (5) 



(6) 



(7) 



Station 



Observer 



Barome- 

 ter in in- 

 ches and 

 at 32° F. 



Observed 



boiling 



point 



corrected 



Calculat- 

 ed value 

 of n. 



Calculat- 

 ed boiling 



point 



from 

 n = 112. 



Diff. 



Gt. E-ungeet River. 



Dr. Hooker. 



29.211 



210.°8 



103.91 



21C°.70 



— C°.10 



Martigny. 



Dr. Forbes. 



28.489 



209.5 



117.29 



209.61 



+ 0.11 



Mont Pi'la. 



M. Marie. 



28.207 



209.05 



115.19 



209.13 



-j- 0.08 



do. „ 



do. 



26.258 



205.48 



114.88 



205.65 



+ 0.17 



do. „ 



do. 



25.819 



204.71 



113.82 



201,83 



+ 0.12 



Churra,KhasiaMts. 



Dr. Hooker. 



25.596 



204.3 



111.68 



204,28 



— 0.02 



Mont Pila. 



M. Marie. 



25.433 



203.88 



115.01 



204.09 



+ 0.21 



Gressonay. 



Dr. Forbes. 



25.143 



203.58 



111.4 



203.54 



— 0.04 



Choongtam. 



Dr. Hooker. 



24.697 



202.5 



112.46 



202.54 



+ 0.04 



Myrung, Khasia. 



do. 



24.453 



201.9 



113.75 



202.06 



+ 0.16 



Prarayon. 



Dr. Forbes. 



23.893 



200.96 



113.0 



201.06 



+ 0.10 



Darjiling. 



Dr. Hooker. 



23.358 



199.6 



114.09 



199.83 



+ 0.23 



Tacul. 



Dr. Forbes. 



23.353 



199.98 



111.7 



199.94 



— 0.04 



do. 



do. 



23.154 



199.48 



112.43 



199.53 



+ 0.05 



St. Bernard. 



do. 



22.674 



198.46 



112.4 



198.51 



+ 0.05 



Zemu Sarndong. 



Dr. Hooker. 



21.605 



195.9 



112.93 



196 03 



+ 0.13 



Col Collon. 



Dr. Forbes. 



20.77 



194.53 



110.16 



194.24 



— 0.29 



Mainom, Sikkim. 



Dr. Hooker. 



20.48 



193.4 



112 19 



193.43 



+ 0.03 



Yeumtong, do. 



do. 



19.49 



191.1 



111.58 



191.02 



— 0.08 



Tungu, do. 



do. 



18.869 



189.5 



111.73 



189.45 



— 0.05 



Mont Blanc. 



Saussure. 



17.133 



187.235 



109.97 



186.89 



— 0.34 



Pichincha. 



M. Wisse. 



17.208 



185.27 



111.26 



185.09 



— 0.18 



Ycumtso, Sikkim. 



Dr. Hooker. 



16.385 



183.2 



109.64 



182.58 



— 0.62 



Sebolah Pass, do. 



do. 



16.928 



181.9 



109.48 



181.21 



— 0.69 



* Edin. Phil. Trans, vol. xv. 



f Given in a second paper by Prof. Forbes, Edin. Phil. Trans, vol. xxi. part 2. 

 X Quoted by Eegnault, Ann. de Chim. ct do Phys. July 1844. 

 § Saussure's boiling-point, 80° R., corresponded to a pressure of 27 French 

 inches. 



