408 Scientific Intelligence. 



An approximate mechanical analysis gave the following results: 



Coarse sand 3 73 per cent. 



Fine sand 22-97 



Fine clay 69-25 



Water 405 



100-00 



The sand was mostly feldspar with traces of quartz and mica. 

 The clay is used for brick making. 



11. Magnetite crystals pseudomorph after pyrite ; by G. C. 

 Hoffmann. (Communicated). — A short time back I had sent me 

 for analysis a sample of iron ore from a deposit which occurs in the 

 vicinity of Kinnear's Mills, township of Leeds, Megantic County, 

 Province of Quebec. It consisted of a very fine crystalline mag- 

 netite and hematite (the former preponderating), through which. 

 was disseminated a large amount of siliceous gangue. Numerous 

 small patches of limonite occurred, interspersed, through the ore, 

 apparently resulting from the decomposition of the pyrites, and 

 there was also a little unaltered pyrite. My assistant, Mr. E. B. 

 Kensick, has made the following observations in regard to some 

 small crystals imbedded in this ore. 



The crystals were in the form of small cubes with faces striated 

 parallel to the edges of the pyritohedron. They were black in 

 color and showed a high metallic luster and brilliant faces. The 

 best crystals had cubic edges measuring l mm or less in length. 

 The crystals were very magnetic, being easily picked up with a 

 magnet. Streak brown. Soluble in aqua regia with very slight 

 residue. Gave off water in closed tube. A crystal weighing 

 •0083 gram lost on ignition -0008 gram, or 8 - 6 per cent of water. 

 This crystal was magnetic after ignition and remained unchanged 

 in appearance. It would appear that the crystals are pseudo- 

 morphs after iron pyrites in an intermediate stage between limo- 

 nite and magnetite. 



12. Anwendimg der Linearprojection zum Berechnen der 

 Krystalle von Dr. Martin Websky. 377 pp. 8vo, with 11 plates. 

 Berlin, 1887, (E. S. Mittler & Sohn). — A peculiar interest attaches 

 to this work in that it was issued after the death of its gifted 

 author; the final supervision has been given by Dr. C. A. Tenne. 

 It is intended to form the third volume of Rose's Elemente der 

 .Krystallographie, a fourth volume in which series was projected 

 by the same author and in part completed. It contains an ex- 

 haustive treatment of the principles and methods of the system of 

 crystallography founded by Weiss and developed by Rose and 

 Quenstedt. Whether this system is the one which, as most con- 

 venient of use, is likely to be generally adopted would seem 

 doubtful. It is, however, a great advantage to the students in 

 this line to have the whole subject presented in a manner which, 

 as regards clearness and completeness, meets every requirement. 

 Numerous examples, worked out in all possible fullness, enable 

 the student to sro forward without a teacher's assistance. 



