432 J. L. Smith on Warwickite. 
To sum up, the evidence presented in this paper renders the 
following statement highly probable. 
When water unites with an anhydrous substance to become 
water of crystallization, the water undergoes the entire con- 
densation. en it unites as water of constitution, the con- 
densation is distributed throughout the molecule. The law of 
this distribution remains to be ascertained. 
Art. XXXVIL— Warwickite; by J. LAWRENCE SMITH, 
Louisville, Ky. 
Iv is several years since Professor Brush and myself, while 
engaged in the re-examination of American minerals, pointed 
out the mineral warwickite as possessing a peculiar composition, 
altogether different from what it had been supposed to have. 
The mineral was first described as a new species by Pro- 
fessor Shepard in 1888 (Am. Journ. Sci., vol, xxxiv), and 
again more fully in 1889 (ibid, vol. xxxvi, p. 813). In both 
of these descriptions, however, he confounded two very dis- 
tinct substances, viz: the mineral proper and an impure variety 
of it, which, while possessing the general crystallographic form, 
contained but a small portion of the true warwickite; in fact, 
one of the crystals that furnished material for his examuna- 
tion was five centimeters long by one centimeter across, and 
had no metallic luster, which luster really marks the true war- 
wickite, especially on the cleavage surfaces. : 
The result of Professor Shepard’s analyses were so different 
from what I have found either in the pure or impure varieties 
that it is needless to give them here. 
Subsequently this mineral was taken up by Pro 
Hunt, and from his results he supposed that he se 
ro. 
