eT OE a a ee eer eee Be gee Oe ate ae NE a ae |. tate SO 
é as AEE Ong oe shes, ie oe 
: 18 the refraction of’ his two rays, and his conclusion thence 
190 J. Wharton on determining the distance 
. 
nate in caustic potash, shows that metastannate of potash is very” 
this point will be given when we come to treat of the silicates 
of lime. The so-called metastannate is therefore rightly named, 
and is not an acid salt nor an unsaturated stannate. And, by 
contrast, the great avidity with which waterglass unites wi 
more base, goes to prove that the silica in it is not a metacid, 
but is of the same kind as that in the normal, crystallized sili- 
cate of soda. 
Manchester, N. H., April 29. 
RT. XIX.—Speculations upon a possible method of determining the 
distance of certain variably colored Stars; by JosEPH WHARTON. 
from another star which the Earth was moving away from. — 
Supposing the ray to strike the Earth from the first of these 
velocities differing by about ~,'-;. Arago found no difference 
t however, rather surprising that any great weight 
should be attached an apparent disproval, by a single test, o 
one merely Inary function of corpuscular light, especially 
Eee: Svan f 
as the test itself is utterly fallacious; for who shall say tt 
retardation by attraction is the onl possible means by which 
emitted light could be refracted? and how can we know that the 
two stars selected by Arago had either no proper motion of theif 
own, or none of a sort to affect his result? eee 
Perhaps the only eases in which we can be sure of receiving — 
starlight of absolutely different velocities are those of such 
binary stars the plane of whose orbit is not at right angles with 
the line from thenee to the Earth, When that line lies in the 
