878 ICE-HOUSE 



solution, which yields on evaporation crystals of hyposulphite of soda ; the reaction 

 being shown by the following equation : 



NaO,S0 2 + S = NaO.S'O 2 (Xa 2 O,SO 2 + S = JTa 2 O,S 2 O 2 ). 



The baryta salt may be obtained in small brilliant crystals, by mixing dilute 

 solutions of chloride of barium and hyposulphite of soda. 



The hyposulphurous acid is incapable of existing in the free state, for almost imme- 

 diately on the addition of an acid to the solution of its salts, it is decomposed into 

 sulphurous acid, with liberation of sulphur. (S 2 2 = SO 2 + S). 



The soluble hyposulphites have the power, in a marked degree, of dissolving certain 

 salts of silver, as the chloride, iodide, &c., which are insoluble in water; forming 

 with them soluble salts, whose solutions possess an intensely sweet tasto, although 

 the solutions of the hyposulphites alone possess a disagreeable bitter taste. 



From the above reaction arises the principal value of the hyposulphite of six In, 

 which is used by the photographer to dissolve off from the photograph, aft er the 

 action of the light on it, all the undecomposed silver salt, thus preventing the further 

 action of the light on the picture. 



A double hyposulphite of soda and gold is used for gilding the daguerreotype plate, 

 and for colouring the positive proof obtained in photographic printing. This double 

 salt may be obtained in a state of purity, by mixing concentrated solutions of 1 part 

 of chloride of gold, and 3 parts of hyposulphite of soda ; by the addition of alcohol it 

 is precipitated ; the precipitate must be re-dissolved in a small quantity of water, and 

 again precipitated by alcohol. 



HYSOW . A green tea. See TEA. 



H YSTATITE. A variety of titaniferous iron from Arendal in Norway. 



An animal of the goat-kind, the hair of which is esteemed for some kinds 

 of manufacture. Two species occur in Europe : the common ibex (Capra Ibex), inha- 

 biting the Alps, and C. Pyrenaicus, found in the Pyrenees : whilst other species are 

 found in Asia and in Africa. The wool of the skyn, or ibex of Little Thibet, has been 

 used in manufacturing certain fabrics. 



ICE. "Water begins to solidify or to become ice at 32 F. See FREEZING. 



ICE-HOUSE. (Glaciere, Fr. ; Eishaus, Ger.) For the uses of common life, in 

 these climates, the most economical and convenient means of refrigeration in hot 

 weather may be procured by laying up a store of ice in winter, in such circumstances 

 as will preserve it solid during summer. 



An ice-house should not be regarded as an object of mere luxury ; in the southern 

 countries of Europe it is considered among people in easy circumstances as an indis- 

 pensable appendage to a country mansion. During the dog days, especially at those 

 periods, and in those districts where the sirocco blows, a lassitude and torpor of mind 

 and body supervene, with indigestion or total loss of appetite, and .sometimes dysen- 

 teries, which are obviously occasioned by the excess of heat, and are to be prevented 

 or counteracted chiefly by the use of cold beverages. By giving tone to the stomach, 

 iced drinks immediately restore the functions of the nervous and muscular systems 

 when they are languid ; while they enable persons in health to endure without mucli 

 inconvenience an atmosphere so close and sultry as would be intolerable without this 

 remedy. Ice-houses, moreover, afford to country gentlemen a great advantage in 

 enabling them to preserve their fish, butcher's moat, dead poultry, and game, which 

 would otherwise, in particular states of the weather, immediately spoil. Considering 

 at how little expense and trouble an ice-house can be constructed, it is surprising that 

 any respectable habitation in the country should not have one attached to it. The 

 simplest and most scientific form is a double cone, that is, two cones joined base to 

 base; the one being of stones or brick-work, sunk under ground, with its apex at tlio 

 bottom, into which the ice is rammed ; tin- other bein<j a e.mieal roof of carpentry, 

 covered with thatch, and pointed at top. The entrance should be placed always on the 

 north side; it should consist of a corridor or porch with double doors, and l>o 

 screened from the sunbeams by a small shrubbery. Such are the principles upoti which 

 an ice-house should be formed; but they will bo better understood by th<; following 

 explanation and figure. 



A dry and sandy soil if possible should be selected ; and here a cavity is to bo dug, 

 about 16 feet in diameter, terminating below like the point of. a sugar-loaf. Its ordi- 



