mi}t-5t. 



V. 



V^m Marum, 7 



Vapour, ftate of, in the atmcfphete, 118 

 —Experiments on that produced from 

 ether, 266 — From fpirit of wine, 269 

 —From liquid ammonia } from muriate 

 of lime; and from mercury and fulphu- 

 ric acid, ayo — See iiifo Steam 



Varnifli, a fine red, 287 



Vauquelin, - 94^ 101 — Experiment^ on 

 gum kino, 232 



Vavaffeur, Le, 70 



Vegetables, aftringent, experiments on, 

 31— Properties which render them va- 

 luable in tanning, 40 



Venturi, 59 



yeffeis,methodofftopping wide-mouthed, 

 6S,, 216 



Vifion, telefcopicj caufes which affeft it, 

 10— ^Can only be diftinft in moift air 

 and uniform temperatures, 16 



Vitreous humour of the eye, chemical 

 examination of, 23 



Volcanos, curious particulars refpedling 

 thofe of South America, 242 



Von Hombolt, on the natural hiftory of 

 South America, and the language and 

 icience of the natives, 242 



W. 



*Walker, Mr. on the proportion of light 

 from candles of different dimenfions, 

 90 — Improvement in his reflefting 

 quadrant, 219 



Walls, experiments and obfervations on 

 the efflorefcences on, 109' — Enquiries 

 into the origin of, 112 



Water, decompofition of, by phofphutet 

 of fulphur, 4 — Its Ipecific caloric is 

 greater than that of ice, 26 — Method 

 of raifing, for the purpofe of refrigera- 

 tinn, 41 — Velocity with which it flows 

 through a vertical pipe, 66— Abforbs 

 one eleventh of its weight of fulphurous 

 acjd gas, 93^ 



Weather, its effefts on telelcopic vifion. 



Wheels, table of the radii of, at a pitch 

 of two inches, 86 — Rules for comput- 

 ing at any other pitch, 88 



White-lead, preparation of, 224 



Wiegleb on the antiquity of the invention 

 ofguhpowder, 71 



Wind increafes the apparent diameter of 

 the ftars, 14 



Woart')' method of fecuring timbers in- 

 jured by the dry rot, 120 



Wollafton on horizontal refraction, 46 



Woltman, 47 



Wooif, Mr. on equalizing the motion of 

 a fteam engine, 218— Self afting and 

 regulating fteam valve, 249 



y. 



Young, Dr. his theory of halos and par- 

 helia, 56 — Defcription of his apparatus 

 for illuftrating the doflrinc of prepon- 

 derance, 59 — His experiment on the 

 velocity of water flowing through a yex- 

 ticai pipe, ib. ' 



Z. 



Zero, natural, inaccuracy of the experl* 

 ments to determine, 28 



ZND or THE SIXTH TOLVMK* 



Printed by W. Stratford, Crown-Court, Tcmple-l»r. 



