386 THE SCIENTIFIC PAPERS OF 



therefore should be clearly understood that the amount of heat 

 engendered by friction could in no case exceed the equivalent head 

 of water, or accelerating force expended ; or, in other words, the 

 772 feet difference of level was necessary to produce as much 

 heat as would raise the temperature of water percolating through 

 narrow passages 1 Fahr. Another explanation, that of the depth 

 to which the water might dip on its way to the well, appeared to 

 him to account much better for the difference of temperature in 

 different levels in the chalk. Of course, if the water dipped to a very 

 great depth and afterwards rose again, the dip would not be pro- 

 ductive of heat by friction, inasmuch as the available heat for 

 friction was due to the difference of final levels, but it might 

 give rise to an increase of temperature owing to the warmer 

 strata which the water had touched on its way. 



In tlie discussion of the Paper 



"ON THE TRANSMISSION OF POWER TO DIS- 

 TANCES," by HENRY ROBINSON, M. Inst. C.E., 



DR. SIEMENS * thought the discussion should not be limited to 

 that portion of the paper which referred to hydraulic transmission 

 and hydraulic presses. The author had dwelt upon the subject of 

 the transmission of power, and Dr. Siemens desired, therefore, to 

 make a few observations on the general question. Hydraulic trans- 

 mission, as had been correctly stated, was the most economical 

 mode at present known. It had the advantage that in forcing 

 water forward very little power was lost. As had been explained, 

 the friction of the hydraulic ram could be reduced almost to a 

 minimum, and the steam power was applied in the most direct 

 manner to that resistance ; in that respect, therefore, hydraulic 

 power could be produced very economically, and the loss of power 



* Excerpt Minutes of Proceedings of the Institution of Civil Engineers, Vol. 

 XLIX. Session 1876-77, pp. 31-34. 



