hi INTRODUCTION TO THE MAKERSTOUN OBSERVATIONS, 1845 ann 1846. 
BAROMETER. 
85. The barometer is by NEwMAN. The tube is 0-552 inch in diameter ; the 
scale is attached to a brass rod, terminating in an ivory point, which at each ob- 
servation is moved by means of an endless screw till it meets its image in the mer- 
cury of the cistern; the cistern is about 3 inches in diameter ; the vernier professes 
to read to 0-002 inch, and that 0-001 inch may be estimated, but the graduation is 
so inexact as to give changes in error from 0-002 to 0-003 inch, when the reading is 
made alternately at the two extremities of the vernier. 
86. In 1841, the barometer was compared indirectly with the standard baro- 
meters of the Royal Society of London, by means of one made by NEWMAN for the 
Douxe of ARGYLE. The comparisons of the DuKE of ARGYLE’s barometer with the 
readings from the flint and crown glass tubes of the Royal Society (both tubes being 
connected with the same cistern) are given, Table 23, Introduction, 1841-2. They 
are not consistent. A consistent series of comparisons of the Makerstoun barometer 
with the Duke of ARGYLE’s is given, Table 24, Introduction, 1841-2. The results 
of these comparisons are 
in. 
Duke of ARGYLE’S barometer minus Royal Society’s crown and flint glass, = + 0-009 
Makerstoun barometer minus DUKE of ARGYLE’S, = + 0:003 
Makerstoun barometer minus Royal Society’s crown and flint glass, = + 0-012 
87. In July 1847, a series of comparisons was made by myself of a barometer 
by TroucHTON, marked B, belonging to Sir Tuomas BrisBaNe, with the flint-glass 
barometer of the Royal Society of London. The same barometer (‘TRouGHTON B) 
was a few days afterwards compared by myself with the Makerstoun standard baro- 
meter: these comparisons are given, Tables 10 and 11. 
TaBLE 9.—Comparisons of the Barometer TRoucuton “ B” with the Flint-Glass 
Standard Barometer of the Royal Society of London, July 2, 1847. 
Royal Society’s ene 
Flint-Glass Standard. pleong Beo aa 
Royal Society 
Standard 
— 
‘ Tempera- Tempera- Temp. of Troughton “B.” 
Height. tie. Herghy. ae Royal Society 
Standard. 
in. a in. cl in. in. 
30-302 63-6 30-262 66-0 30-256 +0-046 
+304 63-9 +267 66-4 -261 043 
-300 64-2 +266 66-8 +259 -041 
+291 64-8 +254 65:8 +251 -040 
+292 64-8 +255 66-2 +251 041 
268 
64-5 
+232 
Corrected to 
+229 
minus 
