THE Geological Survey of the Canadian Department of Mines has published, as Memoir 165 (Ottawa, pp. 225; 1931, 45 cents), a valuable account, under the above title, of an impartial investigation of various methods of geophysical prospecting. Electrical methods were applied in 1928 to the Abana mines property, Quebec, by generous permission of the owning company, and three electrical prospecting companies accepted an invitation from the Geological Survey to demonstrate their methods on this comparatively suitable deposit; the work was done at their own expense, under the observation of officers, both physical and geological, of the Survey. The geological, electric, and magnetic surveys showed that the physical conditions existing in the Abana mineral deposits are complex, but that, nevertheless, the magnetic and electric methods of prospecting, when used intelligently, are feasible and productive of valuable results. The work in any new area must still be to a large extent an original research, requiring the use of highly trained and skilled men. Further work on the Abana property, and elsewhere, was done in 1929, partly in co-operation with the U.S. Bureau of Mines and (in gravity work) with the Dominion Observatory of Canada. At the Errington Mine, Ontario, an area was met “for the first time” where, in the present state of our knowledge, geophysical methods were of small avail, and where the diamond drill under the direction of geologists and mining engineers was the sole guide to further discovery.