426 Scientifie Intelligence. 
study of the work will give an excellent grounding in the science. 
We note that the author, for purposes of classification, divides the 
igneous rocks into plutonic, intrusive and volcanic, a method that 
(with some disadvantages) has much to commend it. iL. 'V. P. 
6. Introduction to the study of Rocks; by L. Fiercusr. 
118 pp. 8vo, 1895. (British Museum of Nat. History, Mineral 
Dept.)—This little work is designed chiefly as a guide to the 
study of the rock collections in the British Museum. The general 
principles of petrology are clearly and compactly stated, though 
in an elementary manner, in keeping with the plan of the work. 
It should prove of service to the general public visiting the 
museum and may well serve as a model guide-book for similar 
institutions elsewhere. Th Vers 
7. Calaverite from Cripple Creek, Colorado ; correction by 
W. F. Hintesranp. (Communicated.)—In my: paper on calav- 
erite from Cripple Creek, Colorado, published in the August num- 
ber of this Journal, I referred to papers by F. C. Knight and by 
Richard Pearce in the Proceedings of the Colorado Scientific 
Society for 1894. My information as to their contents had to be 
obtained at second hand. Now that I have had opportunity to 
read those papers I find to my great regret that I have uninten- 
tionally done the gentlemen an injustice in failing to give them 
further credit. Mr. Knight identified calaverite by analysis and 
showed the iron-tellurium oxidation product to be a ferric tellur-— 
ite. My work was therefore but an elaborate confirmation of his 
prior identification of calaverite. Mr. Pearce is confident that 
sylvanite is a constituent of portions at least of the Cripple Creek 
ores, and his opinion is entitled to great consideration. While 
my paper in no way denies the possible existence of a telluride 
richer in silver than calaverite, it might be inferred that I attrib- 
uted no great weight to Mr. Pearce’s evidence on this point. 
8. Minerals from New South Wales ; Professor A. LivERSIDGE 
has recently announced the discovery of the rare minerals Joleite 
and nantokite at the Broken Hill silver mine in New South 
Wales. The former occurs in interpenetrating cubes, 4 to 7™™ 
- on the edge, of an indigo-blue color; these are implanted upon or 
imbedded in a matrix of hematite and quartz; hardness, 3°5; 
specific gravity 5°02. An analysis by Carmichael and Armstrong 
gave: 
Cl Pb Cu Ag  O(cale.) H,O(cale.) 
13°50 47°20 19'20 8°25 [6-10] 5:44 
The amount of water found by Liversidge in an independent trial 
was 6°39, but this is probably too high. The analysis quoted 
agrees closely with those of the original boleite given by Mallard 
and Cumenge. The nantokite oceurs in pale sea-green particles, 
apparently crystals but indistinct and with a slightly effloresced 
surface; on exposure the color becomes darker, and the surface 
opaque and powdery; hardness 2°5; specific gravity 4-7. An 
analysis by Carmichael and Armstrong gave : 
Cu 64°28 ; Cl 35°92 = 100°20 
