Fmm tíie, Svientiflc American. A none the recent discoveries in science and chemistry, none is more important thau the uses to wliich com ïnoii ammonia can be properly pwt as a leavetiing agent, and whicli indicates that this familiar salt ia hereafter do perform an active part in the prepara tion of our daily food. The carbonate of ammonia is an ex ceedingly yolatile subsiance. Place a small portion of it upou a kuif e aiu holdover a fíame, and it will almos immediately be eiHirely developed into gas and pass off into the air. The gas ihus foruied is a simple composition of uitrngen and hydrogen. No residue is lett from the ammouia. This gives it lts superiority as a leayeuing powei over soda and cieam of tartar usec alone, and has induced lts use as a supplement to these articles. A smal quantity of ammonia in the dough is effective in producing bread that wil be'lighter, sweeter and more wholesoree than that risen by any other leavening agent. When it is acted upon by the heat of baking, the leavening fas that raises the dough is liberated. n this act it uses itself up. as it were; the ammonia is entirely diffuseci, leaving no trace or residu urn whatever. The litfht, lluffv, flaky, appearance, so desirable in biscuits, etc., and so sought after by professional cooks, is said to ue ïmparted to lüem only uy the use of this agent. The bakers and baking powder manufacturéis producing tlie ünest goods have been quick to avail themselves of this useful discovery, and the handsomest and best bread and cake are now largely risen by tha aid of ammonia combined, of course, with other lea veiling material. Ammonu is one of ttie best known products of the laboratory. If, as seems to be justly claimed for it, the application of iis properties to the purposes of cooking, results m giving us lighter and more wholesome bread, biscuit aud cake, it will prove a boon to dyspeptic humanity, and will speedily force itself iuto general use in the new Qeld to vvhich scieuce has assigned it.