INDEX. 
Tones or Modes , in the antient Grecian mufic, an explana- 
tion thereof — — Page 695 
Tourmalin, experiments on it — — 308— 3 39-. 
, fuppofed to be the Lyncurium of Theophraltus 
369 
Tranfitu de proximo veneris fub foie — ■ — 865 
T reatife on a new fet of logarithmic folar tables for finding 
the latitude at fea , obfervations thereon 9 10 
Trees , obfervations on the growth of them — 7 
Turin , account of the weather there for the year 1759 — 842 
V 
Vapours , their amazing force and effeds — 592, 594 
Variation (regular diurnal) of the horizontal magnetic neeale,. 
attempt to account for it - — 398 
. .. — , (irregular) of D° at the time of an aurora bore- 
alis, attempt to account for it — — 399 
Veneris fplanetas) de proximo fub foie tranfitu — 865. 
Vinadio (in the province of Coni in Piedmont) account of. 
the hot baths there — — 839 
Vitriolic waters , account of thofe at Amlwch in the ifle of 
Anglefey — — — 47° 
•, the analyfis thereof — — 472. 
-r, of great efficacy in the cure of many ftub- 
born chronical diteafes — 477' 
Volcanos , many lie together in the fame trad of country 
581. 
almofl always found on the tops of the higheft 
mountains 616 
Underfoot water-wheels , concerning them 101 
, fpecimen of a fet of experiments 
thereon 110 
* , table of the refult of twenty-feven 
fets of experiments thereon — — — 1 15 
. , maxims and obfervations deduced 
from the foregoing experiments thereon — 116 
Urethra , account of two (lones, of remarkable ffiapes and 
fizes, cut out from that of a. young man — 304 
Urine.) , 
