Production of ice per hour............ 25 kilogrammes.
Production of heat units per hour..... 2.5 grammes.
Quantity of ice produced per
kilogramme of coal burned........... 5 kilogrammes.
Water of condensation per hour........ 0.75 cubic meter.
These machines are employed not only for the manufacture of ice, but also in breweries for cooling the air of the cellars and fermenting rooms, or that of the vats themselves; in manufactories of chemical products; in distilleries; in manufactories of aerated waters, etc.
They may also be used in the carrying of meats and other food products across the ocean, and, in a word, in all industries in which it is necessary to obtain artificial cold.
The power necessary to operate apparatus that produce 25 kilogrammes per hour is about that of 3 horses.--Annales Industrielles.
CARBONIC ACID IN THE AIR.
[Footnote: An address before the Paris Academy.]
By M. DUMAS.
Of all the gases that the atmosphere contains, there is one which offers a special interest, as well on account of the part ascribed to it in the mutual interchange going on between the two organic kingdoms, as on account of the relation that it has been observed to occupy between earth, air, and water; this gas is carbonic acid.