1 56 • Mr. Wilson’s Anfwer to the 
became of a conttderable thicknefs. To give the whole a true 
form, the two projecting poles were locked up in two grooves 
when coinciding with the diameter of an iron femi-cirele, 
whole inner edge was fo fattened as to cut away the redundant 
parts of rhe latt coat of the chalk nearly dry, whiltt the globe 
was continuedlv and flovily forced round. By thus repeatedly 
paring off the protuberances, and fupplying newpatte when de- 
ficient, and forcing the globe round againtt the cutting edge as 
before, it at length became quite fmootb and fpherical. After 
this, when (lowly dried, it turned very white, and then the 
fpots or excavations were made in its fur face by boring inftru- 
ments of tteel as in fig. 4. conttrufted in all their cutting edges 
from a fcale of parts of the globe’s diameter. This done, I 
penciled the bottom of the hollows all over black with China 
ink, and dittinguifhed the (helving fides from the full white- 
net's of the outward furface by a (hade of the pencil which 
was darkeft towards the external border. I hope the indulgent; 
reader will excufe me for having been fo particular in regard to 
this artificial fun, as pottibly what I have mentioned may facili- 
tate a like conttruffion, fhould any perfon deem it worth while 
to entertain himfelf with fuch experiments. 
But to proceed ; what has now been intttted on at fo much 
length concerning the (hallow nett and the more gradual (helv- 
ing of fome few (pots, will alfo apply to another objection,, 
which M. de la lande views in a ttrong light. 
Here we find quoted the great fpot in 1719* (ben by Mk 
Cassini ; and, for the fecond time, that of June 3, 1703, leen 
by M. de la hire ; both which, oil their arrival at the limb* 
are (aid to have made an indentation or dark notch in the di(k 
and this phenomenon is mentioned as abfoluteLy incompatible 
with fpots being below the furface. 
It 
