Objections of M. de la lande. 165 
lefs ought fyflems, built upon notions evidently incongruous,, 
to have a place in any modern book of philofophy. This has a 
tendency hill to favour that devious path, that falfe tajie , which 
it concerns philofophy fo much to guard againfl and to dif- 
courage. 
It remains now only to make a few flri&u res upon M. de la 
lande’s theory of the folar fpots, humbly fubmitting them to 
the conlideration of the reader. The import of it is, “ that the 
Ci fpots- as- phenomena arife from dark bodies like rocks, which 
“ by an alternate flux and reflux of the liquid igneous matter 
“ of the fun, fometimes raife their heads above the general fur- 
w face. That part of the opaque rock, which at any time thus 
“ {lands above, gives the appearance of the nucleus, whilfl 
<x thofe parts, which in each lie only a little under the igneous 
“ matter, appear to us as the furrounding umbra.” 
In the firft place it may be remarked, “ that the whole 
w proceeds upon mere fuppofltion .” This, indeed, the au- 
thor himfelf very readily acknowledges. Though, there- 
fore,. it could not be difputed by arguments derived from 
obferv.ation,. yet conjecture of any kind, if equally plau- 
fible, might fitly be employed to fet afide its credit. Choofi ng,. 
however, to avoid a tedious difcuffion of this kind, or to try it 
upon the phenomena which are enumerated in p. 51 1. &c. by 
entering into arbitrary and difputable principles, we fhall con- 
fine ourfelves to fuch particulars as appertain to the more ob- 
vious chara6ter of the fpots, and which alfo leem to be irre- 
eoncileable with the theory ; and firfl of all, in regard to the 
diftinguifhing features of the umbra. 
M. cassini, Mem.. Acad. tom. X. p^ 582. plate 7. and M. 
de la hire, Mem. Acad. 1703, p. 16. and I may add all 
other obfervers, and gill good reprefentations of the fpots, bear 
tefll- 
