E. H. Williams— Crystah of Tourmaline with Orthoclase. 273 



the epochs of great eccentricity might have had may be 

 inferred from the fact that, adopting Mr. OroU's method of esti- 

 mating solar temperature, the mid-summer heat of the northern 

 hemisphere due to solar radiation, was from 40° to 50° higher 

 than it now is. His layer of snow must therefore resist, not 

 merely our present heats, but temperatures ranging from 100° 

 to 150^ Fahrenheit 



The remainder of the argument can be dealt with quite 

 briefly, because it is based on the utterly fallacious results we 

 have just described. The northern hemisphere being cooler 

 the trade winds are thrown farther south. The Gulf Stream 

 being caused, in part, by the trade winds, is thrown into the 

 southern hemisphere, and thus the northern hemisphere is de- 

 prived of this latent source of heat and its temperature falls to 

 a point far below the normal astronomical temperature. Con- 

 sidering separately the propositions that a cooler northern hem- 

 isphere would throw the trade winds south, and that this change 



fore regard Mr. OroU's theory of a connection between the form 



nplex theories is of the less importance that there is no 

 astronomical reason to believe that the solar radiation has been 

 constant during a period of a million of years. 



(T 21, 1876. 



Akt. XXXIII.— 0« crystals of Tourmaline with enveloped Ortho- 

 clase; by Edward H. Williams, Jr. 



[Read before the Chemical and Natural History Society of Lehigh University.] 

 While at Port Henry, N. Y., last July, visiting the newly 

 constructed furnace at Cedar Point, I noticed large sized crystals 

 of tourmaline in some heaps of quartz and feldspar in process 

 of shipment up the lake. 



The feldspar was orthoclase. and of two varieties : one white 

 and compact; the other reddish and much weather-stamed ; the 

 cleavage planes, especially the basal, were more or less covered 

 with a film of sesquioxide of iron. The crystals of tourmalme 

 in the quartz were simple prisms. Those in the feldspar, and in 

 the second variety in particular, were peculiar ; when the feld- 

 spathic matrix was fractured they readily separated from it, 

 and proved to be mere shells of tourmaline filled with feldspar. 

 From want of time I was then unable to visit the locality 

 from which they were taken. When again at Port Henry I 



