295 
trigonometrical measurements at Spitsbergen . 
Deductions. 
AC = 2338,35 feet. AO = 7503,2 feet. 
AD ~ 7029,4 feet. OD = 12842,1 feet. 
CD =6154,2 feet. 
Altitude of the Cone. 
From Station A. From Station C. From the Observatory . 
1645,2 feet. 1643,1 feet. 1641,4 feet. 
The mean of the three results is 1643,2 feet ; and of the 
first and second 1644,15 feet ; and if one-twelfth of the in- 
tercepted arc be added to the zenith distance, to compensate 
for the effects of terrestrial refraction, the first mean will be 
reduced to 1642,8 feet, and the second, which is considered 
the preferable, for reasons already assigned, to 1644 feet. 
Barometrical Measurement. 
The instruments employed for this purpose were a marine 
barometer made by Mr. Jones, and a mountain barometer 
made by Mr. Newman ; the first having a glass cistern, and 
the second an iron cistern : Mr. John Frederic Daniell, 
Fellow of the Royal Society, whose attention had been par- 
ticularly devoted to the construction and improvement of 
meteorological instruments, was kind enough, at my request, 
to superintend their progress through the makers' hands. 
In the construction of these barometers, the tube, cistern, 
and scale, were secured, in the first instance, or designed to 
be secured, immoveably to each other, and the scale was sub- 
sequently graduated from the surface of the mercury in the 
cistern. It happened that this operation was performed in 
