150 TRANSACTIONS OF THE [FEB. 1, 



The chairman pointed out the extreme importance of many of 

 the problems upon which Mr. Dudley is working, and expressed 

 the hope that Mr. Dudley might perfect the rolls for turning out 

 a 60-foot rail straight and cold, upon which he is working. Pro- 

 fessor Hallock remarked the importance of the investigations in 

 their bearing on many problems in physics, whose solutions 

 need the resources of a railroad for a working laboratory. The 

 President, Professor Stevenson, emphasized the debt which the 

 communitj'^ owes to Mr Dudle}'. His improvements in the track 

 mean heavier engines, heavier cars, longer trains, greater speed, 

 reduced rates for passengers and freight, all of which gi-eatly 

 contribute to the general welfare and to the advance of civiliza- 

 tion. 



The next paper was by H. S. Curtis, on " The Advantages of 

 Long Focus Lenses in Landscape Photography." After refer- 

 ring to the unsatisfactory views of distant landscapes that are ob- 

 tained with ordinary lenses, owing to false perspective and lack 

 of detail, the speaker showed how these defects could be 

 remedied by lenses of longer focus. A telescopic combination of 

 40-inch focal length was made available by reversing the lenses 

 and putting the flint and crown about 1 mm. apart. A number 

 of views taken with this combination were thrown on the screen 

 to illustrate the advantages of such lenses. Several pictures 

 were also exhibited that were taken with an ordinar}' spectacle 

 lense of 34 inch focus, stopped to about f inch diameter, which 

 were excellent, and scarcely to be distinguished from those 

 taken with the telescopic lense, or a telephoto combination. 

 Such a spectacle lense can be bought for 10 cents. 



J. F. Kemp remarked the comparative uselessness of ordinary 

 photography in the study of mountain geology, when any 

 notable distance is involved, and expressed the belief that such 

 a simple lense would be of great service in field work. The 

 same opinion was expressed by others. The section then ad- 

 journed. 



Wm. Hallock, 

 Secretary of Section. 



