508 ANNUAL RECORD OF SCIENCE AND INDUSTRY. : 



to one sixth of its bulk, whereas, if the gas had been drawn 

 from an ordinary gas-holder at a pressure of 15 pounds, it 

 would need to be compressed to the one fortieth of its bulk. 

 The gain is, therefore, evidently very great, both in the sav- 

 ing of power and the avoidance of heat evolved by the com- 

 pression. In order to test the power of the pump, it has 

 been run at a pressure of 1000 pounds; but this is higher 

 than is reached in actual practice. The first work with this 

 apparatus was performed May 21 and 22, 1874, when 315 

 pounds of liquid carbonic acid were made in less than two 

 working days, or about nine hours of actual pumping. Great 

 difficulty was at first experienced in the construction of flasks 

 for holding the condensed acid. The cost of making the liq- 

 uid was estimated to have been, in one case, 24.92 cents per 

 pound, and in another case 21 cents per pound. Probably, 

 under more favorable circumstances, the cost would not be 

 greater than 15 cents per pound. In every respect the new 

 apparatus at the station has fulfilled all expectations. By 

 it liquid carbonic acid can be prepared safely, rapidly, and 

 cheaply in any quantity. Hill on Liquid Carbonic Acid, 

 1875. 



A MONSTER BLAST. 



At Crarra Quarry, Cumlodden, England, one of the largest 

 and most successful blasts ever witnessed in that quarter was 

 fired off on Friday afternoon, February 12, the result of 

 which was the dislodgment of upward of 30,000 tons of 

 granite rock. A bore thirty feet long was made into the 

 solid rock, from the end of which, running at right angles, 

 was another bore twenty -five feet in length, making the 

 form of a letter L (sometimes such bores extend in both di- 

 rections from the main bore, making the form of a letter T). 

 At the end of this bore was sunk another one ten feet deep, 

 in which chamber was placed 5300 pouuds of prismatic pow- 

 der. 



AN IMPROVED DRY DOCK. 



The latest improvement in this line is the Tubular Floating 

 Dock, made by Mr. Latimer Clark, of Leeds, England, in con- 

 junction with Mr. John Standfield. The dock is formed by 

 a certain number of tubes, running lengthways .of the dock, 



