232 ANNUAL OF SCIENTIFIC DISCOVERY. 



are the salts of mercury, copper, and zinc. Bichloride of mercury (cor- 

 rosive sublimate) is the material employed in the kyanization of timber, 

 the probable mode of action being its combination with the albumen of 

 the wood, to form an insoluble compound not susceptible of spontane- 

 ous decomposition, and therefore incapable of exciting fermentation. 

 The antiseptic power of corrosive sublimate may be easily tested by 

 mixing a little of it with flour-paste, the decay of which, and the ap- 

 pearance of fungi, are quite prevented by it. Next to corrosive subli- 

 mate in antiseptic value stand the salts of copper and zinc. Chloride of 

 zinc has been patented by Sir W. Burnett for the preservation of wood, 

 sail-cloth, &c., and appears to succeed admirably. For use in the 

 preservation of paper, the sulphate of zinc is better than the chloride, 

 which is to a certain extent deliquescent. 



A series of experiments were made, in the summer of 1840, on the 

 use of metallic and other solutions for the preservation of wood. A 

 deep saw-cut was made all round the circumference of some growing 

 trees near their bases, into which the solutions were introduced by 

 forming a basin of clay beneath the cut ; thus the solution took the 

 place of the ascending sap, and in periods of time varying from one to 

 three days was found to have impregnated even the topmost leaves of 

 trees fifty feet high. The trees were chiefly beech and larch. After 

 impregnation they were felled, and specimens about five feet long by 

 two inches square were cut out, and packed in decaying saw-dust in a 

 warm, damp cellar, where they were left for seven years. The details 

 of the experiment are given in a table, by which the following general 

 results are made to appear : The pieces of wood saturated with sul- 

 phate of copper in the proportion of one pound to one gallon of water, 

 or with acetate of copper in the proportion of one pound to one pint of 

 vinegar and one gallon of water, were found in perfect preservation, 

 clean, dry, and free from fungi ; but the remaining pieces, which 

 were saturated with nitrate of soda, prussiate of potash, acetate of 

 lead, sulphate of iron, common salt, and creosote, presented much decay 

 and a large growth of fungi. The results obtained with solutions oif 

 corrosive sublimate, one eighteenth of a pound to a gallon of water, 

 varied in an anomalous manner. London Chemical Gazette, July. 



SIMPLE PROCESS FOR DEMONSTRATING WITHOUT DANGER THE 



LIQUEFACTION OF GASES. 



BERTHELOT, in the Comptes Rendus for May 27, describes a new 

 process adopted by him for demonstrating the liquefaction of gases, 

 and particularly of carbonic acid, which is founded on the employment 

 of the dilatation of a liquid as the means of pressure. He says, "I 

 take some glass tubes of considerable thickness relatively to their bore, 

 close them at one end, fill with pure dry mercury deprived of air, and 

 then draw them out so as to render them quite capillary at their open 

 end, without diminishing the relation between the thickness and the in- 

 ternal diameter. I then heat the tube in a water-bath, its open point 

 being immersed in a current of the gas which I want to compress. By 

 the dilatation of the mercury a portion is expelled from the tube. 



