36 farmers' and mechanics' journal, 



treated in the next number, will partake of the same character, and 

 will not need to be treated, when other varnishes are considered. 



The following is Dr. Hare's method of bileaching Shell-lac : 



It has been a great desideratum among artists, to rendei shell-lac 

 colorless, as. with the exception of its dark brown hue, it possesses 

 all the properties essential to a good spirit varnish, in a higher de- 

 gree than either of the other resins. A premium of a gold medal, 

 or thirty guineas, " For a varnish made from shell, or seed-lac, 

 ecpially hard, and as fit for use in the arts, as that at present pre- 

 pared from the above substances, but deprived of its coloring mat- 

 ter," has long been, and is still offered, by the Society, in London, 

 for the encouragement of Arts, Manufactures, and Commerce. 

 These ends are perfectly attained, by the process given by Dr. 

 Hare, which leaves nothing to desire, excepting on the score of 

 economy. Were the oxymuriate of potash, to be manufactured in 

 the large way, the two processes, that of making the salt, and of 

 bleaching the resin, might be very advantageously combined. 



Method of bleaching Shell, or Seed-lac. By R. Hare, M. D. 



Dissolve, in an iron kettle, one part of pearlash, in about eight 

 paits of water, add one part of shell, or seed-lac, and heat the 

 whole to ebullition. When the lac is dissolved, cool the solution, 

 and impregnate it with chlorine, till the lac is all precipitated. 



The precipitate is white, but its color deepens by washing and 

 consolidation ; dissolved in alcohol, lac, bleached by the process 

 above-mentioned, yields a varnish, which is as free from color, as 

 any copal varnish. R. H. 



Chlorine, or oxymuriatic acid, may be formed, by mixing, inti- 

 mately, eight parts of common salt, and three of the black oxide 

 of manganese, in powder. This mixture is to be put into a retort ; 

 four parts of sulphuric acid, diluted with an equal weight of water, 

 and afterwards allowed to cool, is to be poured upon the salt and 

 manganese, when the gas will immediately be liberated, and the 

 operation must be quickened, by a moderate heat. If the mixture 

 be made, without the sulphuric acid, and this be added, in small 

 portions, the heat generated by this means, will be sufhcient to dis- 

 engage the gas, without the aid of a lamp. A tube leading from 

 the mouth of the retort, must be passed into ihe resinous solution, 

 when the gas will be absorbed, and the lac precipitated. 



For the Farmers' and Mechanics' Journal. 



Mr. Editor, 



Sir, — In answer to " A Joiner," in your first number, T will state 

 an experiment which 1 made one year since. 1 had about eighty 

 Pannels, which were as green as they were when sawed from the 

 log. I put them into a large kettle,' and boiled them about two 

 hours, and then stuck them over a fire in the shop where they were 



