An Investigation of the Principles upon which a new Self: Registering Barometer 
may be constructed. By Joun Srevetty, Esq. Professor of Natural Philosophy 
in the Belfast Institution. 
Read Noy. 30, 1835. 
My attention having been of late much directed to subjects connected with Me- 
teorology, I could scarcely fail to remark how much time was consumed in making 
and recording observations, and how very limited, as to their extent, were our best 
observations, when considered in relation to the multiplicity of changes which are 
taking place at times when no person is present to observe or record. It is, there- 
fore, an object of much interest to endeavour to construct instruments of every 
description, as far as is practicable, in such a way as that they may register their own 
indications, not only at stated hours of the day, but if possible at all times, and may 
place as clearly as possible the general results before the mind. 
The barometer and the rain gauge are unquestionably two very important instru- 
ments in this science. The following’ observations will, I trust, clearly show how a 
self-registering barometer may be constructed ; and a method of constructing a rain 
gauge capable of registering its own indications, may be so readily deduced from this, 
that it would be a waste of time to allude to it more particularly. 
It is very obvious that if a pencil can be caused to rise and fall through equal dis- 
tances, in such a way as to correspond with equal elevations and depressions of the 
barometer, this pencil may be made to press against a sheet of paper divided by 
twenty-four equidistant vertical lines, which would represent the twenty-four hours 
of the day; while the sheet may be carried by clock-work across the pencil laterally 
or in a direction at right angles to the vertical lines. The pencil would thus trace 
out on the sheet of paper, a curve which would present to the eye a correct view of 
the actual oscillations of the barometer during the several parts of that day; the 
height at each hour, or intervening portion of time, being readily and distinctly trace- 
able. Avsecond portion of this same sheet, or a second sheet, may then have the 
curve for the next day traced upon it similarly ; and so on from day to day; these 
sheets being then dated, and arranged in consecutive order, would afford a correct re- 
gister of the barometer, and thus we should haye within our reach a means of ascer- 
VOL. XVII. 40 
