[ 499 ] 
Scilta, prince of, loft, with a great number of hi# fubjtftn, p, ao$. See EartlfkAb* 
Remarkable cafe of a pregnant woman of that place, p. 2Q4. 
Stl/ufiblc d' Umu, Memoire fur la Maniere tie preparer, avee le moina de perte poiTible, 
le bel fufible d’Urine blanc, et pur, et i’Aeidc phufphorique parfaitement tranfparent, 
by the Duke de Chaulnes, p. 288. 
Smcaton. See Rejijiancc of the Air , Air-pump , 
Srrovj, in melting conftantly abforbs a certain and equal quantity of heat, which is 
employed entirely in giving it fluidity, p. 349. See Cold. 
Sidar Spots. Anfvver to the objections of M. De la Lande, againft thofe fpots being 
excavations in the luminous matter of the fun, together with a fhort examination of 
the views entertained by him upon that fubjecf. By Alexander-Wilfon, M. D. p. 144. 
A former volume of Tranfa&ions referred to, for the doctor’s reafons for concluding that 
all fpots confiding of a dark nucleus and furrounding umbra, are excavations in the 
luminous matter, p. 143. His conviction thereof have been perfected by eight years 
fubf'equent obfervaiions, p. 146. Perfons lefs ufed to examine objeCts with glafies may 
require more palpable dimenfions of future great fpots to behold theie phenomena, ibid. 
The objection that the abfence of the umbra on one fide, when fpots are near the limb, 
is not conllantly anfwered, p. 147. et feq. MefT. Caifini and De la Hire did not think 
any thing of moment depended on a new attention to the form of the fpots, p. 148. 
Though fome few fpots may differ from all the reft, it will not warrant the conclufion 
that no fpot can be an excavation, p. 149. How far fpots, which near the middle 
of the difk appear equal and fimilar in all things, may yet differ from one another as 
excavations, &c. confidered, ibid. DiftinCtion between the neareft and fartheft umbra, , 
p. 150. Examples of the depth of the nucleus and the apparent breadth of the neareft 
umbra, of a fpot of 40" all over, when the plane of the fartheft comes to coincide 
with the vifual ray, p. 151. Remarks thereon, ibid. Method of computing the dif* 
tance of the nucleus from the limb when it is totally hid, p. 152. Why very {hallow 
fpots cannot always be known from the reft, p. 153. Difficulty concerning the great 
depth of the excavations removed, p. 134. Experiments made on a model of the fun 
and its fpots, according to their-proper dimenfions, p. 155. Method of making the 
model, p. r^ij. Obfervations on the dark, notches made in rhe fun’s difk, by thegreat- 
fpots feen in 1719, and June 3, 1703, p. 157, et feq. Thofe notches no proofs of pro- 
jecting nuclei, or irreconcileable to fpots being depreffions in the fun, p. 15S. The, 
only admillible arguments, and which carry perfeft conviction, concerning the nature of 
the fpots, are thofe grounded upon the principles of optical projection, p. 159. Op- 
tical and phyfical arguments defined, p. 160. Dark and limited fphere of humaiv 
reafon, in regard to the economy of the fun, p. r6i. That the fpots are really exca- 
vations or depreffions, is a fact cltablifhed by optical arguments, ibid, and the only 
one the author contends for, p. 163, Strictures on M. de la Lande's theory of the 
folar-fpots, p. .165 — 1,68>. 
Sptrrmateii ■ 
