for the Promotion of Science. 397 
are entirely’ unacted on by-sulphuric or hydrochloric acids. By expo- 
sing these materials in fine powder to prolonged digestion in the acid, 
vdaedhl acid a 
liquid furnished chlorid of se crate wah ch “of aluminium 
is communication drew forth some er ase remarks dad con- 
firmatory statements from Professors Hare, Henry, Ww. B. Rogers, R. 
E. eee Silliman, and Mr. Hunt. , 
some ee agi dependent 1 bi the Progressive Mo- 
ites, of Lig By Prof. Srepuen Arexanper of Prine n, N. J. 
Afier Se saing to the rechgnizat e fecuot 1 the aun heated 4 
light, and that which is ordinarily termed planetary aberration, the 
author more particularly explained the dragging of the shadows of the 
earth and other pianatte first previously noticed ‘by himself in a. com- 
munieation to the American Philosophical Society... Pr of. A. then 
proceeded to the consideration of the case in which light passed through 
the transparent envelop of a ‘body in motion, and observed that inas- 
much as the t theory of undulations réquired that the ether should be 
possessed of inertia, and the inertia.of our atmosphere must be in- 
comparably greater ~ that of the met it would seem to follow, 
of the same through the » siapeabhone a is ‘i produce HE ated 
tion, which, in so far as the ear ’s motion “was concerned, would be 
the opposite to that which actually exists, aberration bei th in 
mode and measure, what it ought to ye the earth had no ead 
molecules. When tert the quantity of atmosphere to be travers- 
ed was so great that. light must be nearly absorbed, some sensible 
juesti A: 
others, bprdering that. edge of the earth’s shadow, into which the moon 
entered, “at the time of the last lunat eclipse, but which was less dis- 
tact on ee side at which the moon emer * and showed that these 
1ena were fabs! nt. with the oc ag ag of such an impulse, 
ied by the ifg of thes 
pe An bs sae that these "Sadaidevalions might have a 
n. the. question of'a systematic aberration of the double 
