482 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



water is supplied to wet the globes. A number of such 

 pairs of globes being fastened to the axle, sufficient force is 

 produced to turn a delicate clock-work. An apparatus con- 

 structed by Bernardi, with globes having a diameter of three 

 fourths of an inch, and with arms three inches long, has 

 worked for three months without change ; in which period 

 he calculates that the quantity of heat consumed by the 

 apparatus has been equivalent to sixty revolutions of the 

 wheel per day. 13 J3, III., 80. 



THE PYKOLETEE. 



A new apparatus for the preservation of life and property 

 from fire at sea, called the Pyroleter, or fire destroyer, was 

 lately tested in England. A barge of some 40 to 50 tons' 

 burden was fitted up for the purpose of the experiment. 

 Along the entire length and width of the hold cotton-waste, 

 shavings, and small wood saturated with oil and naphtha was 

 placed to about the depth of two feet, and ignited on a given 

 signal, within two minutes of which time dense volumes of 

 flame and smoke issued from the open hatchways. The 

 hatchways were then battened down, and the apparatus being 

 set to work, the flames were completely extinguished within 

 four minutes. The Pyroleter, by means of which this result 

 was effected, is a small pump, which draws from tubs placed 

 on each side of it simultaneous supplies of diluted hydro- 

 chloric acid and a solution of sodium bicarbonate. Both 

 mixtures then meet in a generator and instantaneously pass 

 into a separator, whence dry carbonic acid gas is evolved, 

 and passes through fixed pipes to the locale of the fire, which 

 it speedily suppresses. The chief merit of the invention is 

 that a fire can be readily extinguished by dry gas with the 

 assurance of no damage to the cargo therefrom. 



ETCHING IKON. 



Much time and attention has been devoted by Professor 

 Kick, of Prague, to the subject of etching iron with acids. 

 His method for arriving at a knowledge of the quality of 

 iron or steel is not a new one, having been used with some 

 success for a long time, but the care with which the Pro- 

 fessor has conducted his experiments makes them exceed- 

 ingly valuable. 



