January 10, 1896.] 



SCIENCE. 



in small blocks along gliding planes across 

 the optic axis without altering its direction. 

 Prof. Van Hise in closing admitted the pos- 

 sibility of chemical recrystallization, citing 

 in illustration some m.arbles which exhib- 

 ited it, but mentioned others that are full of 

 strained and crushed crystals. The papel- 

 was one of the most important of the meet- 

 ings and is indispensable to all students of 

 metamorphic districts. 



Proofs of the Rising of the Land around Hud- 

 son Bay. EoBEET Bell, Ottawa, Canada. 

 The speaker cited well preserved sea 

 margins and grand terraces, especially on 

 the eastern coast; lines of driftwood above 

 highest tides; debris along old shore lines 

 in the woods on the west side at a distance 

 from the highest tides; islands near shore 

 becoming peninsulas within the human 

 period; drying of salt water marshes; the 

 character of the lower parts of streams 

 showing recession of the sea; shoaling of 

 mouths of rivers and formation of new 

 islands and bars in historic times; other 

 historic evidence; successive growth of 

 marsh plants, bushes, poplars, spruces, etc., 

 as the land rises; beach dwellings and 

 other shore works of the Eskimos now ele- 

 vated to considerable heights; fresh char- 

 acter of fossil shells, etc., in clays and 

 sands; deep water deposits elevated above 

 the sea level at comparatively recent 

 periods; similar phenomena on the eastern 

 coast of the Labrador peninsula; bones of 

 whales, etc., on elevated ground in Hudson 

 Strait; raised terraces and beaches in the 

 northwestern part of Hudson Bay; general 

 shoaling of the water, extension of shores 

 and enlargement of islands. 



The paper was discussed by one or two 

 speakers without, however, bringing out 

 material points. 



Possible Depth of Mining and Boring. Alfred 

 C. Lane, Houghton, Mich. 

 This paper discussed some of the diffi- 



culties in deep mining, especially the rise 

 in temperature, and considered what the 

 most favorable circumstances are and the 

 most effective way of overcoming the diffi- 

 culties, and how far we may expect that the 

 earth's crust will be penetrated. The ex- 

 penses were plotted as the abscissas of a 

 curve of which the depths furnished the or- 

 dinates. Ten thousand feet appeared to be 

 approximately the limit. The depths of 

 some of the shafts in the copper country of 

 Lake Superior were cited, and the hope was 

 expressed that, when the ultimate practical 

 depth has been reached, a purely scientific 

 bore hole be started at the bottom, before 

 the shaft is abandoned, and sent down sev- 

 eral thousand feet further. In the discus- 

 sion that followed special attention was paid 

 to the rate of the increase of temperature as 

 we go down. One speaker cited the recent 

 results published by Alexander Agassiz in 

 the American Journal of Science, Decem- 

 ber, 1895, p. 503, as 1° F. for each 223.7 

 feet down to 4,580. For this result a mean 

 rock temperature at 105 feet of 59° F. is 

 used, whereas the mean annual tempera- 

 ture of Calumet is about 40°, and practi- 

 cally this temperature of 40° has been deter- 

 mined at slight depths in other neighboring 

 mines. A mean annual temperature of 59° F. 

 is not met north of Kentucky and this fact 

 makes corroboration desirable before impor- 

 tant inferences are based on the later and 

 excessively low gradients. 



Notes on Glaciers. Harey Fielding Reid, 



Baltimore, Md. 



Dr. Reid referred, in opening the paper, 

 to his recent efforts to get reliable data 

 on the variations of American glaciers. 

 Mr. Willis reports that the Pyallup gla- 

 cier on Mt. Rainier had retreated 200- 

 300 yards and the Carbon glacier 100— 

 200 feet. In British Columbia the lUicUi- 

 waet was observed to recede in 1890 and 

 1894. Dr. Eeid then gave a most interest- 



