18 65.] Physics. 499 



course all parasitic ferments are destroyed, and the wines keep well 

 after it. 



Our readers are already acquainted with some of the ingenious 

 propositions of M. Tellier to utilize the force evolved in the passage 

 of liquefied ammoniacal gas from the liquid to the gaseous state, and 

 its condensation again by contact with water. He has now proposed 

 some further applications of liquid ammonia. These applications are 

 founded upon two indisputable truths: — 1. In empty spaces liquids 

 spontaneously give off vapour, the tension of which immediately 

 reaches its maximum. 2. In two spaces communicating, kept at equal 

 temperatures, and containing one liquid, there is always evaporation 

 in the warmer space and condensation in the colder. The first appli- 

 cation suggested is a means of cooling the air of the saloon and cabins 

 of a steamer, say, going down the Ked Sea, where the want of cool air 

 is generally experienced. For this purpose he puts liquid ammonia 

 in a sort of tubular boiler, the tubes of which are in free communica- 

 tion with the air and the saloon to be cooled, while the boiler itself is 

 in communication with a worm and receiver bathed with a stream of 

 cold water. The warm air, as it passes through the tubes, parts with 

 its caloric to vapourize the ammonia, and so reaches the cabin delight- 

 fully cool, while the ammonia goes on to the receiver to be again con- 

 densed. On its way it is utilized to drive a ventilator, supply cold 

 water to the receiver, and pump itself back again to the generator ; but 

 by what contrivances and machinery is not stated. A modification of 

 the same plan, as M. Tellier states, is also adapted to cool theatres 

 and other places of entertainment, as well as ships' cabins. More in- 

 genious still is the idea of making the solar rays volatilize ammonia, 

 and so in parching heats manoeuvre a pump or pumps which shall 

 irrigate the thirsty earth with refreshing streams, and so make the sun 

 partially undo its own work. More practicable, perhaps, is the idea 

 of using the liquid ammonia to cool the wort in breweries and main- 

 tain a constant temperature during fermentation. Eemembering that 

 all these ends are to be effected without loss of material, we must give 

 M. Tellier the credit of being one of the greatest inventors or most in- 

 genious theorists of modern times. 



A very useful contrivance has been described by Erlenmeyer for 

 managing the application of heat in the distillation of liquids with 

 high-boiling points. A sand-bath is very inconvenient, and a clay- 

 coated retort is often out of the question. The Doctor therefore 

 suggests surrounding the retort with short fibres of asbestos, which he 

 keeps in their place by means of a wire gauze. Such an asbestos 

 bath appears very simple, and will no doubt be perfectly efficacious. 



Electricity. — M. Matteucci has studied the battery recently intro- 

 duced by M. Blanc, who employs a plate of zinc and a plate of lead 

 covered with a very thin deposit of copper, which are placed in a 

 solution of common salt, with which is mixed a quantity of flowers of 

 sulphur. This battery appears to be very useful for telegraphic pur- 



2 m 2 



