364 
SECOND REPORT- 1832 . 
present owes the best portion of its scientific character, was 
made by an Englishman,—the doctrine of Definite Proportions: 
and if Englishmen seriously propose to themselves the task, we 
are justified by the history of Science in asserting that none are 
more likely than they to solve the great problem of mineralogy 
which now offers itself,—the connexion of chemical composi¬ 
tion and crystalline form. Besides this great problem, it has 
appeared in the course of this Report, that various other ques¬ 
tions of narrower extent remain to be decided by experiment. 
We will recapitulate a few of these. 
1°. To determine the optical differences on which depend 
the distinctions of the different kinds of lustre, metallic , ada¬ 
mantine , vitreous, resinous, pearly . 
2°. To determine whether the oblique rhombic prism is a 
real system, or is a hemihedral form of a right prism. 
3°. To determine the limits of magnitude and simplicity in 
crystallometrical ratios. 
4°. To determine whether chemical groups are strictly iso- 
morphous, or only pie siomorphous. 
5°. To determine whether the angles of plesiomorphous cry¬ 
stals are separated by definite or by indefinite steps. 
6°. To determine what are the differences of chemical com¬ 
position corresponding to differences of optical structure in re¬ 
sembling minerals, as apophyllite, tesselite, leucocyclite. 
I will further add that the formation of good collections of 
well-crystallized minerals, (in which should be included suites of 
artificial crystals, both from fusion and solution,) and ail arrange¬ 
ments which make such collections accessible to the working 
mineralogist, are circumstances highly important to the progress 
of mineralogical knowledge. 
The determination of many of the above and similar very 
essential questions, must depend on observations made on cry¬ 
stals which are generally difficult to procure sufficiently perfect 
and transparent for such researches, there being often only a 
few known specimens in the world which would answer the 
purpose, and these having an enormous and fantastical money 
value affixed to them as rarities. I conceive, therefore, that all 
persons and Societies possessing splendid and beautiful mi¬ 
nerals, if they are desirous that such possessions should be of 
use to the advancement of science, cannot in any other way have 
nearly so good a chance of furthering this object, as by placing 
these treasures at the disposal of the intelligent and skilful 
optical or chemical experimenter. While the unique crystal 
stands on its shelf unmeasured by the goniometer, unslit by the 
optical lapidary, unanalysed by the chemist, —it is merely a piece 
