384 Bibliography. 
by repeated simultaneous observations of the best barometers, the true 
elevation of all the important mountain elevations, which constitute 
such an important feature in New Hampshire scenery, and also, by 
proper astronomical observations, to fix their geographical position. 
Mount La Fayette, the most elevated point in the group, commonly 
known as the Franconia Notch, was found to be five thousand and sixty 
seven feet high, and its latitude, N. 44° 8’ 59.4. Mount Washington, 
the highest point in New England, was measured with every precau- 
tion to insure accuracy, and an interesting account is given in the re- 
port of the modes adopted to ensure this end. The result was, that 
the summit of Mount Washington is N. 44° 16’ 34.48; and the 
height, as ascertained by a series of barometrical and thermometrical 
observations, made under the most favorable circumstances, during 
twelve hours, was six thousand two hundred and twenty six feet above 
the high-water mark in Portsmouth harbor ; the same, calculated by a 
series of observations, was six thousand two hundred and twenty eight 
feet, making but two feet difference in the elevations, and in single 
observations the difference is but six feet. geet 
The most interesting mineralogical discovery made during this ex- 
ploration, was that in the town of Jackson, of a vein: of OXIDE OF TIN, 
in a powerful lode of arsenical pyrites. This is the first, instance 
of the occurrence of this metal in America in any tangible quanuly, 
and although the amount of the tin hitherto observed is not great, yet 
the discovery, in its indications, may be looked on as one of the most 
valuable metallurgic observations yet made among us. — tail 
Dr. Jackson also mentions the occurrence-of a mineral at Unity, 1 
which he gives the name of ‘chlorophyllite, and is inclined to consider 
as néw? it'will be seen by referenve to page 357 of the present nume 
ber, that this opinion is there discussed. goa 
The chemical department of the report evinces, as usual, much 
tivity and patience in the laboratory, and when the final report appea!s> 
by 
Hircucocx, LL. D. 2 vols. 4to. pp. 831, 54 plates. Amherst, 
€: Adams; Northampton, 8. Butler. 1841.—It is with great pleasure we 
erica, and the first (except Prof. H. D. Rogers’ report on New Jer- 
sey) of that series of final reports which are to form the grand sum 
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