308 Alger's Localities of Rare Minerals, 
resembles Ledererite ; their hardness, lustre, color and. blow- 
pipe characters are the same. The appearance of hexahedral 
cleavage, on which Dr. Jackson originally founded the chief 
claim of the latter to the character of a new species, was only 
imperfectly produced by heating the crystals, and not by 
ordinary mechanical cleavage. This could not be effected, 
the mineral breaking, in all directions, with a vitreous fracture. 
Dr. Jackson agrees, with me, that it can no longer be retained 
as a distinct species. 
While preparing my edition of Phillips’s Mineralogy, I re- 
quested Mr. Hayes and Dr. Jackson to make several analyses 
for me with particular reference to that work. As some of 
these have not appeared in any other form, I wish now to 
make a permanent record of them, in order that they may be 
seen where they might not otherwise reach. The first are of 
the Nova Scotia Chabasite (Acadiolite,) which Hoffmann has 
distinguished from common Chabasite, by its containing 3 per 
cent. more silica, and for which Rammelsberg has given a 
formula differing somewhat from that of Chabasite. (See first 
part of this article.) 
Silica, 52.02 52.20 
Alumina, 17.88 18.27 
Lime, 24 6.58 
Potash 3.03 
Soda, 4.07 l dei 
Water, 18.30 20.52 
.. 99.60, Hayes. 99.69, Hayes. 
These results agree with those obtained by Hoffmann,’ in his 
analysis of the same mineral, the specimens of which were 
presented to him by Charles Cramer, Esq., of St. Petersburg. 
Washingtonite of Shepard, analyzed by Mr. J. S. Kendall, 
under the direction of Dr. Jackson, gave these results: 
1 Amer. Jour, of Sc. vol. xxx. p. 366. 
