APPENDIX. 



353 



TABLE XVIII. 



Solutions for the impregnation of wood which is exposed to the atmos- 

 phere, for the purpose of preserving it from decay. 



Tar. 



Sulphate of Copper. 



Sulphate of Zinc. 



Sulphate of Iron. 



Sulphate of Lime. 



Sulphate of JMagnesia. 



Sulphate of Barytes. 



Sulphate of Soda. 



Alum. 



Carbonate of Soda. 



Carbonate of Potash. 



Carbonate of Barytes. 



Sulphuric Acid. 



Acid of Tar, (pyroligneous acid.) 



Common Salt. 



Vegetable Oils. 



Animal Oils. 



Coal Oil, (Naphtha,) 



Resins. 



Quick-lime. 



Glue. 



Corrosive sublimate.* 



Nitrate of Potash. 



Arsenical Pyrites water, — (water 

 containing arsenical acid.) 



Peat JMoss, (containing tannin.) 



Creosote and Eupion. 



Crude Acetate, or pyrolignite of iron. 



Peroxide of Tin. 



Oxide of Copper. 



Nitrate of Copper. 



Acetate of Copper. 



Solution of Bitumen, in oil of tur- 

 pentine. 



Yellow Cromate of Potash. 



Refuse Lime-water of Gas-works. 



Caoutchouc, dissolved in naptha. 



Drying Oil. 



Beeswax, dissolved in turpentine- 



IChloride of Zinc. 



* Corrosive sublimate is one of the most efficient of all these antiseptic applications. 

 It was proposed by Mr. Kyan as a preventive of dry rot, under the idea of its acting 

 as a poison to the fungi and insects, wliich were the supposed cause of the disease. 

 But this explanation of the action of corrosive sublimate is no longer tenable, as ii is 

 generally admitted that the fungi and insects are not to be considered the origin, but 

 the result, of the dry roi. It has been suggested that its action depends en the forma- 

 tion of a compound of lignum, or pure woody fibre, with corrosive sublimate, which re- 

 sists decomposition in circumstances where pure lignum is liable to decay. But pure 

 lignum possesses no tendency to combine with corrosive sublimate. The action of 

 this substance is in reality confined to the albumen, with which it unites to form an 

 insoluble compound, not susceptible of spontaneous decomposition, and, therefore, in- 

 capable of exciting fermentation. Vegetable and animal ipatters, the most prone to 

 decomposition, are completely deprived of their property of putrefaction and fermenta- 

 tion by the contact of corrosive sublimate. It is on this account advantageously em- 

 ployed as a means of preserving 3.nimal and vegetable substances. Its expensiveness 

 in this country is a great obstacle to its extensive employment on timber used for build- 

 ing purposes, for fences, bridges. Ice. There is scarcely any antisceptic application 

 BO effectual. By Mr. Kyan's process, the timber to be impregnated, is sawed up into 

 planks, and soaked for seven or eight days in a solution containing one pound of cor- 

 rosive sublimate to five gallons of water. The Impregnation may be easily effected in 

 an open tank ; though the best way is to impregnate the timber by placing it in an 

 air-tight box, from wiiich the air has been exhausted as much as possible by a pump. 

 The solution then enters the pores of wood freely, being pressed into them by a force 

 equal to about one hundred pounds to the square inch. — ParneWs Applied Chemistry. 



