[ 4«r ] 
nual fhower of beneficial truly vital air, ibid. p. 433. Obfervatior.s thereon, p. 435. 
— 43 8- Benefits to be drawn from this new difcovery, p. 438. 
Vegetation , uncommon. See Hemp Seed. 
Velocity of the rays of light. An experiment propofed for determining, by the aberra- 
tion of ihe fixed liars, whether the rays of light, in pervading ‘different media, 
change their velocity according to the laws which refult from Sir Ifaac Newton’s 
ideas concerning the caufe of refraction, and for afeertaining their velocity in every 
medium whofe refpeaive denfity is known, p. 58. See Leibnitz , RefiaAion. Proofs 
that the aberrations in a telefcope filled with a denfe fluid will precifely agree 
with that of Dr. Bradley’s, only in the cafe of the rays moving fwifterin the medium 
ihan in air, in the ratio afligned by Sir Ifaac Newton, and that this famenefs of 
aberration will itfelf be a proof of light being fo accelerated within the telefcope, 
p. 60. etfeq. Propofitions concerning the viewing a fubjedt, when the denfe fluid 
within the telefcope is confined by objedt-glafles of any figure, p. 65. et leq. 
Vince, rev. Samuel. See Infinite Series. 
Vifion. See Double Stars. 
Vitriolic acid. See Infiammable Air , Saline Subfiances. 
P olatile alkali . Saline Subfiances , Priefiley. 
Volcanos. See Iron Works , Smelting Houfcs. Marine fait the bafis, or one of the chief 
and moll abundant menjlrua , which excite the effervefcence of, iv. The appearance 
of lightnings in their eruptions explained, xxxiii. 
Volta, Mr. See Infiammable Air , Elefiricity. 
w._ 
Wales , Mr. See Population. 
Wedgwood, Jofian. See Thermometer. 
White, Dr. William. His obfervations on the bills of mortality at York, p, 33. See 
Tork. 
Wilfon , Patrick. His propofed experiment by the aberration of the fixed fiars, &c. See 
V do city of the Rays of Light. 
Withering, Dr. William. See Mineral Subfiances , Saline Subfiances. 
Y. 
York. Obfervations on the bills of mortality at, p. 33. Table of the births and 
burials there from Aug. 5, 172S, to Aug. 3, 1735, P* 37 * Of births and burials 
there from Jan. 1, 1770, to Dec. 1, 1776 inclufive, p. 3S. Of biiths and burials 
there, with the proportion of males and females, annually, from January 1, 1770, 
to 
