TRANSACTIONS OF THE SECTIONS. 
25 
agent, lias been totally unsuccessful. In the experiment brought 
under the notice of the Section, the velocity with which the poles of 
any number of magnets are reversed is inconceivable, and the whole 
lifting power is applied with the greatest possible advantage directly 
to the mechanism; circumstances which appear to justify the au¬ 
thor’s expectation that the application of magnetism to machinery, as 
a moving power, will ultimately be successful. 
Description of a New Dipping Needle. By R. W. Fox. 
[A description of this instrument has been already printed by the 
author.] 
Abstract of Hansteen’s Researches in Magnetism. By Capt. 
Sabine. 
[This paper will be printed in the next volume of Transactions.] 
Account of Magnetic Observations in Ireland. By Capt. Sabine 
and Prof. Lloyd ; communicated by the latter. 
[This will be printed in the next volume of Transactions.] 
Results of three years and a half hourly Observations with the 
Thermometer at Plymouth. By W. Snow Harris. 
[This Paper will be printed in the next volume of Transactions.] 
On the Measurement of Heights by common Thermometers. By 
Lieut.-Col. Sykes. 
The thermometric instrument for measuring heights invented by 
the late Rev. F. J. H. Wollaston, though very sensible, has been found 
by the author and Mr. James Prinsep of Calcutta too fragile and too 
expensive for rough work. After the destruction of three of these in¬ 
struments, Col. Sykes had recourse to common thermometers, which, 
with certain precautions, he found to answer extremely well, and 
having tested their indications by contemporaneous barometrical ob¬ 
servations, he was enabled to present a table of comparative results. 
The thermometer to be observed was uniformly kept in the water, 
which was made to boil violently, about 2 inches above the bottom of 
the pot; two thermometers were successively employed, the differ¬ 
ence of their scales being known ; different tables of the elastic force 
of steam were employed in the reduction; and from the whole of 
the results the author has collected a few into a table, calculated 
to show the limits of error, of thermometric measures of heights 
in India, when the boiling temperature of the level of the sea is 
assumed to be constantly 212°; of single barometrical observa¬ 
tions, when the pressure at the level of the sea is assumed to be 
30,000 inches, (mean temperature in both cases 82°;) and of corre- 
sponding barometrical observations. The general agreement of all 
the results, by whatever method obtained, is remarkable, and is con¬ 
sidered by Col. Sykes as justifying his opinion that common thermo¬ 
meters may be satisfactorily used to supply the place of barometers 
in measuring heights, where great accuracy is not required. 
