120 M E M O I R S of fbe 
feem to be entire as they were originally, are at the top flat 
and rough, without any ftriated lines; thofe that lie low 
to the fea are wafhed fmooth ; and others, that feem to have 
their natural tops blown or wafhed off, are fbme concave, and 
others convex. The high bank hanging over the caufway 
on that fide which lies next it, and towards the fea, leenns 
to be for the moft part compofed of the common fort of craggy 
rock, only there are a few irregular pillars on the eaft-fide, and 
fome firther on the north, called the Looms^ or Organs, flanding 
on the fide of a hill, the pillars in the middle being the longefl, 
and thole on each fide of them becoming fhorter and fhorter ; but 
juft over the caufway, the tops of fome pillars appear out of the 
fides of the hill, neither ftanding or lying fiat, but floping. The 
leveral fides of one and the fame pillar are, as in the planes of 
cryftals, of very unequal breadths; and in fuch as are hexagonal, 
a broader fide always lubtends, or is oppofite to, a narrower ; 
which fort of geometry, nature alio obfcrves in the formation of 
cryftals. 
jt^e Evaporation of Water in a clofe Room-^ by Mr. Edm. 
Halley. Phil. Tranf. N° 212. p. 183. 
IN order to explain the circulation of vapours experimentally, 
Mr. Halley caufed an experiment of the quantity of vapours 
rifing fimply from the warmth of the water, without being ex- 
pofed either to fun or wind, to be made in GrefJjam college; and 
adding up into one fum the evaporations of the whole year, he 
found, that from a furface, as near as could be meafured, of eight 
fquare inches, there did evaporate i6z^i grains of water, which 
is 54 cubic inches of water, and that divided by eight inches, the 
area of the furface of the water, fhcws that the depth of water 
evaporated in one year, amounts to eight inches. But this is by 
much too little to anfwer the experiments of the French, who 
found that it rained 19 inches of water in a year at'Payis; or thofe 
of Mr. 'loivriky, who, by a long continued fcries of obiervations, 
hath fafiiciently Proved, that in T.av.capire, at the foot of the 
hills, there falls above 40 inches of water in a whole year; whence 
it is very obvious, that the fun and wind are much more the 
caufes of evaporation than any internal heat or agitation of the 
water. The fame obfcrvations do alio ihew <^\^\ odd quality in 
the vapours of water, which is thar of adhering to the furface 
whence they exhaled, whj^h they cloath, as it were, with a 
fleece of vaporous air, which once in^el.Jng it, the vapours rife 
afterwards in much lels quantity; which appeared by the fmall 
quantity 
