320 



Atomic Weight of Mercury, 



Example of Table ii.— Convert 2205.23 Toises 

 (height of Mount Blanc above the Lake of Ge 

 neva) into English Feet. 



Toises. 

 2000 

 200 

 5 

 .2 

 .03 



Eng. Feet, 

 = 12789.90 

 = 1278.99 

 = 31.97 

 = 1.28 

 = .19 



2205.23 = 14102.33 



Example of Table hi.— Gay Lussac ascended 

 with a balloon to the height of 7028.3 Metres, as 

 determined by a barometer, — convert this into 

 English Feet. 



Metres. Eng. Feet. 

 7000 = 22966.29 

 20 = 65.62 

 8 = 26.25 

 .3 = 0.98 



7028 3 = 23059.14 



= 4 Miles 1939 Feet. 



TABLE IV. REDUCTION OF DECIMETRES, CENTIMETRES, AND 

 MILLIMETRES, TO ENGLISH INCHES. 

 From De La Bechfee Geological Manual. 



Dec. 



Inches. 



Cent. 



Inches, j 



Milli. 



Inches. 



1 



3.937 



1 



0.393 1 



1 



0.039 



2 



7.874 



2 



0.787 



2 



0.078 



3 



11.811 



3 



1.181 



3 



0.118 



4 



15.748 



4 



1.574 



4 



0.157 



5 



19.685 



5 



1.968 



5 



0.196 



6 



23.622 



6 



2.362 



6 



0.236 



7 



27.559 



7 



2.755 



7 



0.275 



8 



31.496 



8 



3.149 



8 



0.314 



9 



35.433 



9 



3.543 



9 



0.354 



10 



39.370 



10 



a.937 1 



10 



0.393 



ON THE ATOMIC WEIGHT OF MERCURY. 



To the Editor of the JMonthly American Journal of Geology, &c. 



Sir, — I beg leave to call your attention to a matter, which, 

 though brought before the scientific public some time ^nce, 

 seems not to have received that attention from chemists, which 

 its importance ought to command. 



Three years ago, Mr. S. AUinson, jr. of your city, published 

 an article in Silliman's Journal, in which he maintained that the 

 atomic weight of mercury, as stated in the current treatises on 

 chemistry, was incorrect, and offered several good reasons for his 

 opinion. This article (in a much improved and enlarged form) 

 was subsequently published in the Journal of the Philadelphia 

 College of Pharmacy, for July, 1829 ; and to this Journal I would 

 refer those who may wish to see the experiments and observa- 

 tions, which induced Mr. A. to call in question the correctness of 

 the commonly received statements. Now I desire that some 

 practical chemist or any one else, who may have the apparatus 

 and skill requisite, would decide who is in the right. Mr. A., or 

 the text books. 



The doctrine of chemical equivalents is very justly regarded 

 as one of the most interesting and important departments of 

 chemistry; and it is certainly much to be desired that every thing 



