518 The American Naturalist [j une , 



are without effect upon it of any kind. The principal minerals stud- 

 ied by the author that yield definite and distinctive results are hauyne, 

 sodalite, scapolite, chabazite, calcite, witherite, cerussite and anglesite 

 and others of less importance. The method of manipulation neces- 

 sary to produce good results is described in each case with great min- 



Dufet 1 describes a method for the determination of the comparative 

 values of the indices of refraction by means of the prism and total 

 reflection, and Lavenir 2 gives an account of a new process by which 

 the optical orientation of any crystal may be determined. 



A report on " The Mineral Resources of the Province of Quebec," 

 by Ells 3 , contains a history of the various mining industries of the 

 district. In the same annual report Hoffmann 4 publishes a list of the 

 minerals occurring in Canada, and Ingalls 5 gives statistics relating to 

 the production and exportation of the mineral products of Canada. 



'Bull. Soc. Franc, d. Min., xiv, p. 130. 



3 Pt. K. Ann. Rep. Can. Geol. Survey, 1888-89. 



