J. P. Kimball on Sodalite and Eleolite. 65 
stretches away through the tail, a region of wave interference. 
No wonder, then, that comets turn their tails from the sun, and, 
at perihelion, whisk them, though of enormous lengths, through 
celestial arcs well nigh equal to a semi-circumference, in a few 
ours. is is no more surprising than that opaque bodies 
throw their shadows from the Juminous sources whose light they 
intercept. The curvature, which is so remarkable a feature in 
the tail, is but the simple effect of the comet’s orbital velocity, 
and the progressive motion of lig 
If the principles here cited be well founded, then will the 
zodiacal light find an easy solution; and the great oblateness of 
its spheroidal figure must be taken as evidence that the component 
molecular motions in the sun are greater in the direction of the 
solar axis than in any other. 
West Point, Oct. 25th, 1859. 
Art. VIII.—On Sodalite and Eleolite from Salem, Massachusetts ; 
by J. P. Kimpaut, Ph.D. 
For a knowledge of this locality of the occurrence of the two 
‘Tare silicates, sodalite and eleeolite, we are greatly indebted to 
Gilbert L. Streeter, Esq., of Salem, as well as to several other 
gentlemen of the same city. Fortunately, Mr. Streeter ver 
z carefully observed their mode of occurrence, and, together with 
'. Cheever, Esq., and Rev. 8. Johnson, Jr., collected choice 
imens of them. The best of these are in the possession of 
the Essex Institute, Salem, to the curator of which, Dr. Hen 
heatland, I owe in a great measure the privilege of examining 
W 
them 
eae | along the northern side of the Neck, towards Hospital 
+ oint."* They were first noticed ma “block of compact syen- 
ite resting upon the bank, the end of which presented a beanti- 
fal coloring of blue and greenish white, with specks of black. 
Upon examination these conspicuous minerals were seen to b 
se wg onda amg connected with the block of 
yenite.” 
Mr. Streeter subsequently discovered what undoubtedly was 
© continuation of the same vein. This traversed an erratic 
block of the same rock, imbedded in the drift, of which the 
small block, just mentioned, was a fragment. The vein is de- 
Scribed to have been about six feet in width, and to have dimin- 
* G. L. Streeter: Essex Institute Proceedings, ii, 153. ¢ Ib. 
SECOND SERIES, Vor. XXIX, No. 85.—JAN., 1860. 
9 
