t 6 5+ ] 
State of the barometer and thermometer, with what rain fell, at Lyndon, in Rut- 
land, for the year 177 C, p. 370. 
The proportion that mean months bear to the whole years at feveral periods, with 
rcfpett to rain at Lyndon, in Rutland, p. 371. 
For applying a correction to difcover an equal heat in the quickfilver of the ther- 
mometer, p. 377. 
Concerning the depreflion of quickfilver in the barometer, p. 382. 
Obfervations made with the variation compafs belonging to the Royal Society, 
p. 392, 393. 
Obfervations made with the dipping-needle, p. 400. 
Experiments with a machine, determining what proportion or quantity of me- 
chanical power is expounded in giving the body different degrees of velocity, 
p. 463. 
1 Tattenhall , an enumeration of its inhabitants in the year 1774, p. 165. Chriilenings 
and burials there, ibid. 
Tertianasy fo much dreaded in the ifland of Minorca, enquiry into the caufes of, 
p. 440 — 445. Two or three whole families died in confequence of putrid moifture, 
p. 445. Medicine ufed with fuccefs in this diforder, p. 446. 
Theorems for finding, in all cafes, the difference between the values of annuities pay- 
able yearly, and of the fame annuities payable half-yearly, quarterly, or mo- 
mently, p. 109 — 128. See Annuities. 
Theorems mathematical. 
If from the angles at the bafe of any right-lined triangle, right lines be drawn to the 
alternate angles of rhombi, deferibed upon the oppofite fides, and applied recipro- 
cally to the fides produced ; and from the vertex, through the interfe&ion of thefe 
lines, a right line be drawn to meet the bafe : the fegments of the bafe, made 
thereby, will have to each other the duplicate proportion of the fides, p. 73, &c. 
If from the angles at the bafe of any right-lined triangle, right lines be drawn to the 
alternate angles of rhombi deferibed on the other two fides, and reciprocally applied 
to them produced, and through the interfeClion of thefe lines, a right line be drawn 
from the vertex to the bafe; the redlangle contained by the fines of the angles at 
the extremities of one of the fides will be equal to the redangle contained by the 
fines of the angles at the extremities of the other; and the parallelepiped contained 
by the fines of the angles of one of thofe triangles, into which the original one is 
divided by the faid line drawn from the vertex, will be equal to the parallelepiped 
contained by the fines of the angles of the other, p. 83, 86. 
If from the angles at the hypotenufe of any right-angled right-lined triangle right 
lines be drawn to the alternate angles of fquares deferibed on the fides containing 
the right angle, and from the point where the right line drawn from the right 
angle, through their interfeclion, meets the hypotenufe, right lines be drawn to the 
points, where thefe lines meet the fides; the lines fo drawn will make equal angles 
with the hypotenufe, and the right line drawn from the right angle to meet it; and 
a will 
