1835.] the Advancement of Science. 223 



should not be forgotten. Steeps of this description required 

 an increased power, and the engines capable of working on 

 the general line of road, would not be capable of exerting 

 an increased force. There were only two ways of ascending 

 sudden ascents, one by the agency of an additional engine, 

 find the other, by having the whole train pulled up by means 

 of a rope. The additional engine, would occasion much 

 additional expense, for the supply of them would always be 

 preserved, and the men should be paid their wages whether 

 wanting or not. The use of the rope would occasion an 

 enormous waste of power, and he mentioned the instance 

 of a place, where an ascent of 1 foot in 106 occurred. 

 The rope was five miles long, and its weight was 60,000 

 pounds. Dr. Lardner next referred to one point on 

 which he seemed to consider that engines generally were 

 at variance with what was correct. He contended that the 

 heat of the fire is directly proportional to the quantity of 

 the steam allowed to escape in a definite time into the flue, 

 and consequently that half the number of blasts of steam 

 projected into the chimney in an engine going up a hill, 

 would have the same effect in exciting the fire as double the 

 number of blasts of half the condensation, when the engine 

 was running on a level plane. 



Friday^ Sth August, — Mr. Ettrick read an account of cer- 

 tain improvements on steam engines, and on securing the 

 seams of boilers, of a machine for drilling boiler plates, and 

 of an astronomical clock. 



9. Mr. Cheverton read a communication on the sculp- 

 ture of busts by machinery, exhibiting beautiful specimens. 



10. Mr. Grubb made some very able and practical obser- 

 vations on an improved model for mounting an equatorial 

 instrument, adopted by Edward J. Cooper, M. P., of Mack- 

 roe Castle, county Sligo. 



Mr. Cooper bore testimony to the excellence of the in- 

 strument, as also to the talent and perseverance of Mr. 

 Grubb in his scientific improvements and inventions. 



11. Lieutenant Denham stated some details in reference, 

 to the vibratory effects of rail-roads, especially over tunnels. 

 A discussion then took place between Dr. Lardner and Mr. 

 Vignolles, on the disadvantages arising from acclivities on 

 rail -roads, which appeared to the Section as over-rated by 

 Dr. Lardner. 



