S62 
INDEX. 
Mjrrh^ obfervations upon, made in Abyffinia, In the year 1771, p. 408. MjTrh of 
moderns nothing different from that of the ancients, ibid. From whence it is brought^ 
ibid. Troglodyte myrrh preferred to that of Arabia, p. 409. Why modern myrrh 
is generally worfe in quality than the myrrh of the ancients, Ibid. W^hy in fomc years 
this myrrh may not exilf, ibid. The myrrh of the Troglodytes not all of equal 
goodnefs, p. 410. The caufe of this difference, and how the belf fort is procured, 
p. 410, 41 1. How new myrrh gets an oily covering, p. 412. A fpecimen of what 
the Troglodyte myrrh was, p. 412, 413. How to know Arabian myrrh from Abyf-. 
finlan, p. 41 7. 
N. 
where the fand-martins build theirs, p. 273. 
'Nooth, Dr. his defcription of an apparatus for impregnating water with fixed air, p. 
See Water, 
"Northamptmi^ average of deaths there, p. 427. 
O. 
Oats, experiments on their power of generating heat, p. 4^r. 
Occultaiio/is of 7 and a Tauri, at Leicelfer, p. 370. From Mr. Wargentin, p. 28 u 
Oil, caufes hot water to boil brifkly, p. 492. 
Ofocalpafwn, conjedtures concerning, p. 413 — 416. 
Otaheite, obfervations on the nofe flute ot, p. 7a. Sec Finte. 
OuJton, in Chefhire, an account of a machine for raifing water there, p. 277. See Machhiu 
P. 
Tapllion do Montagna. See Sand-martin, 
Pendle-hill and Peniiygant, their height, p. 498. 
Pcnny^fMcight, See Weight and Meafures. 
Percival, Dr. Thaimas, his obfervatioirs on the ftate of population in Manehefler .Tn^ 
other adjacent places, concluded, p. 327... See MajicheJler. 
Petrarch, canon of the cathedral at Padua, relicks of him near Arqua, p.>35. 
Phofphoric /par, mineral acid air produced from, p. 394. 
Pliny, his eight critical days of the moon’s age, p. i 8g — 190. 
Poks, magnetic, how to difcover the poles of a fpherical loadflone, p. 79, Generally 
found, upon uvo points diametrically oppolite to one another, ibid. The magnetic 
poles of the earth feem obliquely fltuated to one another, ibid. Where fituated un- 
known, ibid. Accurate obfervations with a good dipping-needle, as near thefe mag- 
netic poles as poffible, the furefl way to complete the magnetic theory of this globe,. 
P* 79> 80. 
