Peacock, Mr. James. See Architecture, &c. 
Phlogijiicatcd Air , whether many different fuMances are not in reality confounded togs* 
ther under this name, p. 381. 
Phlogifton, See Air. 
Phofphoric Light . See Combit/lion . 
Pigott , Edward, Efq. See Variable Stars . 
Polypus, has no anus, p.341. 
Price, Dr. See Combuflion . 
Priejlley , Rev. Jofeph. See and iVater, 
Pringle , Col. See Bafe» 
Pyrometer . See 
R. 
Pain, See Barometer, &c. 
Ramfden, Mr. his curious beam compaffes, p. 402. See Bd/e. His ea!y and fimpl® 
way ®f obtaining the fcale of his pyrometer, p. 471. 
Reed-wren. See Mdtacilla. 
Richmond, in Surrey, method of boring for water there, p. 6* 
Riga Red-wood, more fuiceptible of the effects of moifture than Nevv-England white- 
wood, p. 435. 
Rotatory Motion. Of the Rotatory Motion of a Body of any Form whatever, revolving^ 
without Reflraint, about any Axis palling through its Center of Gravity, by Mr. 
John Landen, p, 311. When the axis, about which a body is made to revolve, is not 
a permanent one, the centrifugal force of its particles will didurb its rotatory motion, 
&c. p.312. To determine in what track, and at what rate, the poles of fuch mo- 
mentary axis will be varied, not an un intending proportion, ibid. The folutions 
of that problem by M. Leonhard Euler, M. D’Alembert, and M. John Albert Euler., 
rectified by the author, ibid, Difference between him and the above gentlemen con- 
cerning the angular velocity and the momentum of rotation, p. 313. How to find a 
parallelopipedon that being by fome force or forces made to revolve about an axis» 
with a certain angular velocity, fhall move exactly in the fame manner as any other 
given body, if made to revolve with the fame force, about an axis palling through 
its centre of gravity, p.315. Tab. X. fig. t. explained, ibid. Method of finding 
how a parallelopipedon will revolve about fucceffive momentary axes palling 'through 
its center of gravity, p. 318. Fig. 2. and 3. explained, p. 31S. 322. Fig. 4. ditto, 
0.321. Fig. 5. ditto, ibid. Errors of M. Euler pointed out, p. 327, 328. To 
which M. D’Alembert’s feem nearly fimilar, p. 328. 
6 
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