CHEMISTRY. 21-1 



ciently fluid, when it is drawn off into another vessel, where it is left to get 

 a little cooler, an even temperature being maintained throughout the mass by 

 keeping it well stirred. The mixture is next run off into moulds containing 

 wicks, and heated, as before stated, up from 112 to 132; and the tempera- 

 ture is gradually lowered down to from 59<> to 67, when the candles may be 

 removed from the moulds. The wicks may be composed of from 60 to 150 

 threads, woven, plaited, or united in any suitable manner, to form a capillary 

 column, large in bulk, and at the same time very divided ; and they may be 

 made to burn either so as to require snuffing or not. Vegetable wax, if sub- 

 mitted to too high a temperature, turns black ; while if the temperature be 

 not high enough, it curdles, and does not produce a perfect candle. Newton's 

 London Journal. 



IMPROVEMENTS IX BLEACHIXG CLOTH AXD PAPER. 



Two patents have recently been taken out in Europe for different methods 

 of bleaching. The one by Pierre J. Davis, of Paris, is quite an original process ; 

 he employs for this purpose chloroform in a state of gas. The cotton fabrics 

 are placed in a close wooden box to which steam is admitted from a boiler, 

 at a pressure of 60 Ibs. to the square inch ; this box contains a liquor made of 

 carbonate of soda (crystallized soda), of a strength about 4 in the hydrometer, 

 and the goods are steamed in this for about two hours, then allowed to cool. 

 The box must have a safety valve on it, and an emission steam pipe. After 

 this the goods are taken out, dripped, and placed in another close wooden box 

 lined with lead, but communicating by a pipe with a chloroform generator. 

 This consists of an earthenware vessel into which 3 Ibs. of bleaching powder 

 (chloride of lime), 3 Ibs. of slacked lime, a quarter of a pound of alcohol, and 

 9 Ibs. of water, are placed together and stirred. About one pound of hydro- 

 chloric acid is then poured upon these materials, when the chloroform gas 

 begins to generate, the cover is then put on the generator, and the gas con- 

 ducted by a pipe into the leaden chamber which contains the fabrics. This 

 gas half bleaches the goods hi the course of an hour or so ; when hydro- 

 gen gas is introduced into the box, to expel the chloroform. The goods are 

 then submitted a second time, for a few hours, to the action of chloroform gas, 

 made of a like quantity of materials, but distilled from a zinc retort heated to 

 145 Fah. After this operation oxygen gas is admitted to the goods, which 

 imparts to ihern a bluish shade. They are then taken out, washed, dried, and 

 finished. 



The other patent is that of H. Hodgkinson, of Belfast, Ireland, and consists 

 of a steam-tight box hah* filled with bleaching liquor (chloride of lime) heated 

 by steam, and having within this box a revolving wheel made with apart- 

 ments containing the fabrics to be operated upon. Each apartment has a 

 door to put in and take out the goods, also opening in the bottom, to allow 

 the entrance of the liquor. As this wheel revolves, the goods are dashed, as it 

 vrere, through the hot liquor hi the box, and are thus bleached rapidly and 

 evenly. 



By the common method of bleaching, the liquors used are all cold, because 

 the chlorine gas is expelled by a very moderate heat, but as the gas operates 



11 



