to ascertain a Standard of Weight and Measure. 177 
APPENDIX. 
(§. 44.) Since the writing of the preceding Memoir, I have 
had an opportunity of examining three other scales, divided 
into inches, or equal parts, of considerable authority in this 
country, having been executed by the late Mr. J. Bird. I have 
also compared the old standard in the Exchequer, of the time 
of Hen. VII. and which is considered to be the most ancient 
authority of this sort now subsisting : these observations, I 
flatter myself, the Royal Society will be desirous of possessing. 
(§. 45.) The first of the abovementioned scales belonged to 
the late General Roy, and was purchased by him at Mr. 
Short’s sale, the celebrated optician ; it was used by him in 
his operations of measuring a base line on Hounslow Heath. 
(See Phil. Trans. Vol. LXXV.) It was originally the property 
of Mr. G. Graham, has the name of Jonathan Sisson en- 
A ■■■' >r ) 
graven upon it, but is known to have been divided by Mr. 
Bird, who then worked with old Mr. Sisson. It is 42 inches 
long, divided into tenths, with a vernier of 100 at one end, and 
of 50 at the other, giving the subdivisions of 5ooths,and loooths, 
of an inch. 
(§. 4 6 .) The second is in the possession of Alexander Aubert, 
Esq. and formerly belonged to Mr. Harris, of the Tower; 
contains 60 inches, divided into loths, with a vernier, like that 
of the preceding. It is one inch broad, and 0,2 thick. 
(§• 47-) The third was presented by Alexander Aubert, 
Esq. and the late Admiral Campbell, Mr. Bird’s executors, to 
the Royal Society, in whose custody it now remains. It con- 
sists of a brass rod, g 2,4 inches long, 0,57 inch broad, and 
mdgcxcviii. A a 
