[ 509 ] 
when firft fhut up, ibid. Accounted for by Dr. Prieflley, ibid. The author aban- 
dons the opinion that air is a modification of water, p. 335- In every cafe, wherein 
dephlogifticated air has been produced, fubftances have been employed, fome of 
whofe conftituent parts have a ftrong attraction for phlogifton, p. 336. Phaenomena 
obferved from combinations of the nitrous acids with earths from which the deph'o- 
gifticated air is obtained with lefs heat than from nitre itfelf, p. 338. Experiment to 
examine whether the phlogifton was furnifhed by the earths, p. 339. Ditto to deter- 
mine whether any part of the acid entered into the compofition of the air, ibid. 
Ditto to determine the quantity of acid in the receiving water and in the fublimate, 
p- 341. Ditto of the diftillation of dephlogifticated air from cubic nitre in a giafs 
veffel, p. 342. If any of the acid of the nitre enters into the compofition of the 
dephlogifticated air, it is avery fmall part; and it rather feems that the acid, or part 
of it, unites itfelf fo firmly to the phlogiiton as to lofe its attra€tion for water, p. 
344. Any acid, which can beara red heat, may perhaps concur in the production 
of dephlogifticated air, ibid. Dephlogiiticated air obtained from the pure calces of 
metals may be attributed to the calces themfelves, ibid. General reafoning on the 
fubject, p. 346. Mr. Scheele’s hypothefis, p. 347. The heat extricated during the 
combuttion cf inflammable and dephlogifticated air is much greater than it appears 
to be, p. 348. By an experiment of Dr. Prieitley’s it appears, that nitre can pro- 
duce one-half of its weight of dephlogiiticated air, p. 349. Dephlogifticated air, in 
uniting to the phlogifton of fulphur, produces as much heat as in uniting with the 
phlogifton of phofphorous, ibid. Dephlogifticated air unites completely with 
about twice its bulk of the inflammable air from metals, ibid) Experiments by Meff. 
Lavoifier and De la Place, p. 350. The union of phlogiflon, in different propor- 
tions with dephlogifticated air, does not extricate different quantities of heat, ibid. 
Charcoal, according to Dr. Prieftley, when freed from fixed air, and other air which 
it imbibes from the atmofphere, is almoft wholly convertible into phlogifton, p. 
351. Enquiry whether all the heat let loofe in thefe experiments was contained in 
the dephlogifticated air, p. 352. Not to be anfwered without many new experi- 
ments, p. 353. 
Air, Sequel to the foregoing Paper, in a fubfequent letter from the fame, p. 354- 
Cautions neceffary to thofe who may chufe to repeat the experiment m entioned in the 
foregoing paper, ibid.—356. Some circumftances pointed out which may caufe 
“variations in the refults, p. 356. 
Alchorne, Mr. Stanefby. See Gold. 
Algol, Obfervation of the Variation of Light in that Star, in a letter from Sir Henry 
C. Englefield, Bart. p.1. The laft vifible period when Mr. Aubert and Sir Henry 
obferved it, ibid. Refult of feveral obfervaticns made at different times from mid- 
night to 2h. p. 2. The diminution of Algol fully confirmed, and the accuracy of 
Mr. Goodricke’s period afcertained, ibid. Sce Algol cn the index in the laf? volume. 
Uw uy2 Algol, 
