Fish may also be preserved in a dry state, and perfectly fresh, by means of sugar alone. Fresh fish may be thus kept for some days, so as to be as good when boiled as if just caught. If dried and kept free from mouldiness, there seems no limit to their preservation; and they are much more nutritious in this way than when salted. This process is particularly valuable in making what is called ‘kippered salmon,’ and the fish preserved in this manner are far superior in quality and flavour to those which are salted or smoked. A few tablespoonfuls of brown sugar are sufficient for a salmon of five or six pounds’ weight; and if salt be desired, a teaspoonful or two may be added. Saltpetre may be used instead of salt, if it be wished to make the kipper hard.
The well-known property possessed by ether, alcohol, pyroxylic spirit, chloroform, and certain other hydrocarbons, of averting putrefaction, has been thus applied by M. Robin:—He encloses the meat or other substances to be preserved in a glass case, along with a sponge or a capsule containing the preservative liquid, which latter is continually evolved in a vaporous condition, and exercises the preservative agency. In this way the vapours of hydrocyanic acid are found to be very efficacious. Camphor is thus employed in the MUMMY CASES in the British Museum.
It has been asserted by Mr George Hamilton that in an atmosphere of binoxide of nitrogen, in the dark, flesh preserves its natural colour and freshness for about five months; and eats well provided it be boiled in open vessels, to expel nitrous fumes. See Candying, Egg, Fish, Fruit, Milk, Pickles, Potting, Preserves, Salting, Smoking, Stuffing, Vegetable substances, &c.
PUT′TY. This name is given to the following
preparations (when used alone. ‘Glazier’s putty’ is generally indicated):—
Putty, Glazier’s. From whiting made into a stiff paste with drying oil. It is used to fix panes of glass in sashes, to fill holes and cracks in wood before painting it, &c.
Putty, Plasterer’s. A fine cement used by plasterers, made of lime only. It differs from ‘FINE STUFF’ in the absence of hair.
Putty, Polisher’s. Syn. Putty powder, Calcine; Cineres stanni, Stanni oxydum crudum, L. A crude peroxide of tin, obtained by exposing metallic tin in a reverberatory furnace, and raking off the dross as it forms; this is afterwards calcined until it becomes whitish, and is then reduced to powder. Another method is to melt tin with rather more than an equal weight of lead, and then to rapidly raise the heat so as to render the mixed metal red hot, when the tin will be immediately flung out in the state of ‘putty’ or ‘peroxide.’ The products of both these processes are very hard, and are used for polishing glass and japan work, and to colour opaque white enamel. See Tin.
Putty, To Soften. Take 1 lb. of American pearlash and 3 lbs. of quick-lime. After slaking the lime in water add the pearlash, and let the mixture be made of a consistence about the same as that of paint. When required for use apply it to both sides of the glass, and let it remain in contact with the putty for twelve hours; after which the putty will have become so softened that the glass may be removed from the frame without any difficulty.
PUZZOLA′NA. Puozzolana, or, more correctly, Puzzuolana, is a volcanic ash found at Puzzuoli, near Naples. When mixed with lime it forms an excellent hydraulic cement. A good FACTITIOUS PUZZOLANA may be made by heating a mixture of 3 bushels of clay and 1 bushel of fresh-slaked lime for some hours to redness. (M. Bruyere.) See Cement and Mortar.