398 C. Dewey on the Level of Lake Ontario. 
Oxygen, : 5 i 
Silica, 42°82 22°25 22°25 
Magnesia, 54:4 od aa : 
Protoxyd of iron, 1-47 "38 29°34 l 
Alumina, trace. — 
Lime, "85 24 
Ignition, 0-76 
100°34 
a 
This ratio gives the formula of chrysolite R*8i, The analysis 
fully confirms Dr. Smith’s conclusions, and shows that boltonite 
is a magnesian chrysolite, that is, unlike other varieties of the 
species, it is a silicate of magnesia and not of magnesia and iron. 
Yale Analytical Labratory, Dec. 1st, 1858. 
Art. XLVI— Varying Level of Lake Ontario; by Prof. C. DEwsyY. 
were made at the Port of Genesee, Charlotte, at the mouth of 
Genesee River, by order of the Government. They have been 
reported annually in the local papers, and in the Regents raft 
and I now present the measures and results obtained for the 
thirteen past years. : 
Variations of the Level of Lake Ontario, for the enumerated years, oe 
ured a fixed point downwards to the water.—The larger 
measure, the lower the level. 
a TABLE.—Measure in inches. 
Years, Ltan \F ee eee Pe ae Se Pe a ae ee a 
; Bil salas as las ao of aR 9 | ee 
1846 | 51 | 54/ 48 | 45 | 42| 39 | 39} 42 45| 45/| 48 | 45| 45:2; 15 Low. 
1847 | 48 | 42! 36 | 36 | 29| 25/25) 25) 36\ 39 46 358 23 Bel'wmesn 
1848 | 29/34/43 38] 38| 37 | 38] 39 | 44/ 49| 54 13) 2 a 
1849 | 50) 50| 52 46 | 36) 33 | 44| 39| 45/ 38/ 38| 41/427, 19| * | 
1850 | 45| 40| 40 | 40| 32| 99| 34| 46 | 47/ 52/| 55| 43/ 41-9, 26 
W851 | 44) 54/ 48/47/44 38/35/38) 42| 47) 53/51 450 19 Low. 
1852 | 50| 51) 48 | 44/26} 26 | 22| 24 | 30/| 93| 38/34/1347, 29 Higher 
1853 | 35 | 32) 32 | 25/20) 14 | 27/20/24) 98) 38/39/2783 25 High 
1854 |39| 39) 38 | 38/ 97| 94/ 95/97/36) 44) 48/ 50/362 26 Bel 
1855 | 52} 53 | 36 | 40 | 40 | 36| 34! 36 36/ 34) 33/33) 386 20 |’ 
1856 | 35| 35 33 | 31/23 | 18 | 93 30 | 37| 46| 53| 53/347, 35 Higher 
1857 | 54) 56) 46 | 44/ 35/ 24/ 19/ 12/14] 9/ 24/22/3000 47 high. 
1858 |19| 13/13/18) 4) 6| 4| 2) 8/12| 14/16|109 17 Very Ne 
Means, 42 | 42! 39/38 '30 27/98/99 | 34/36/41 40/298 25 | 
4 
