ELISHA MITCHELL SCIENTIFIC SOCIETY. 149 



discussed and the present position of the vai-ious governments of the world 

 towards it was mentioned in detail. 



The Secretary reported two new members: 



Prof. W. A. Withers, Raleigh, N. C. 



Prof. C. E. Brewer, Wake Forest, N. C. 



During the past nionth one liundred and ten books and pamphlets were 



received. 



forty-ninth meeting. 



December 3, 1889. 



The Society was called to order by Prof. Holmes. He announced that Prof. 

 Cain would read the first paper of the evening on 



29. Preliminary' Location of Railways as Affected by Topography. 



Certain topographical features were first discussed — also crests of water- 

 sheds or ridges, gaps and saddles in ridges, streams and branches with their 

 rates of fall in flat, hilly, and mountainous countries respectively, which gen- 

 erally determine the maximum gradients lO use. Low points of ridges as 

 "points in the line" were considered, such gaps generally being'indicated by 

 streams having their heads very near together and flowing in opposite direc- 

 tions, or by streams running near each other. Railway locations were then 

 divided into ridge lines, generally the cheapest and easiest to maintain, lines 

 running along the streams, giving often easy gradients, but with many culverts 

 and bridges, lines crossing the general direction of the streams at right angles, 

 and lines running oliquely across the streams and corresponding ridges, often 

 giving the most expensive lines. Illustrations from the author's experience 

 were given of eacli character of line and the principles of location. The 

 subject of locating railways in the mountains was next given, the subject of 

 "making distance" to overcome the great elevations being illustrated by 

 locations in Western North Carolina, across the Blue Ridge, in the Rocky 

 Mountains, and across the Alps. 



30. The Velocipede Railway was next described by Prof. Gore. 



Some details as to construction and the results of experiments with this new 

 style of railway were given and its advantages and disadvantages were com- 

 pared with the present double-track road. 



The following papers were read by title: 



31. Addendum to the Minerals and Mineral Localities of North Carolina. 

 By W. E. Hidden. (This paper appears in full in this Journal). if 



32. Nematode Root-Galls. By Prof. George F. Atkinson. (This paper is 

 published in this Journal). 



33. A Tube-building Spider, By Prof. W. L. Poteat. (This paper is pub- 

 lished in this Journal). 



The Secretary and Treasurer then presented their reports of those ofEces 

 for the year. These reports are appended. 



