DESERIPTION of a SELF-REGISTERING BAROMETER. By 
. the Rev. ARTHUR M‘GWIRE. Communicated by the Rev.. 
M.. YOUNG, .D.D.\S. F. T..C. D.. and ,.M.R. L.A. 
AAAA Is a piece of paper, upon which are hours and minutes Read May 75. 
marked by perpendicular lines; and degrees and tenths of - mos 
degrees! by ‘horizontal limes. This:paper is in a frame, whith 
is moved horizontally by clock-work. 
BC Isa fixed pale, on which the numbers decreafe from |.C’ 
to B. 
D Is a pencil which flides into a tube whofe center is fixed to 
the cylinder of the barometer at the point where the mercury 
- ftands when at 293, to trace the rife and fall of the baro-. 
meter. 
E Is a vernier, fixed to the cylinder of the barometer at the: 
point where the mercury ftands when at. 29}, to fubdivide : 
the divifion upon the fcale B C. 
FR 
