34 R. Emery—Relative proportion of Iron and 
Iil.— Correction for Altitude. 
Difference of altitude. of | Diff faltitud c. 
0 feet to 240 0 || 5050 feet to 6531 +11 
a . +1 5531 =“ 6012 12 
“1203 2 6012“ 6493 13 
1203" «1683 3 6493 6974 14 
1683“ 2164 4 6974 7455 15 
2164“ 2645 5 | = 745B 7936 16 
2645 “ 3126 6 7936 8417 17 
3126 = 3607 7 8417 “ 8898 18 
360T  “ 4088 8 8898 ‘ 9378 19 
4088 “ 4569 9 9378  “ 9860 +20 
4569 “ 65050 +10 ‘9860 = 10341 2 
Nore.— and c’ are given in units of the fifth decimal place. 
Art. VIIl.—On the relative proportion of Iron and Sulphur in the 
‘* Pyrite” contained in several specimens of lowa Coal; by — 
Rusu Emery. 3 
pounds remaining. This solution was vibe gigs: to dryness ; 
decomposition. In Nos. 1, 2, 5 and 10, large amounts of Ca 
were found; in No. 3, a very small quantity; none in the 
