TANNINE. 77 



Work that is turned and polished in the lathe, may be so heated 

 by the tViction. as to be nnuch more conveniently lackered, than 

 when heated in any other way. 



The forei^ointi directions apply only to smooth work, such as is 

 either polished or burnished. Chased, or wrought work, snch as 

 leating, &c. cannot be lackered with (he kind of brush before de- 

 scribed ; one wilh tine, stilf hairs, called titch-hair, is used, and 

 this, instead of being passed over the article, is dabbed on, until 

 the surface is regularly covered. 



The most careful workmen do not return the lacker from the 

 cup. into the bottle, but pour it into another, where it is allowed to 

 accumulate, and to settle, when it will be as good as at first. 



When the lackering is finished, the brush may be scraped upon 

 the wire, and afterwards wij)ed by pressure between paper, 'i'his 

 will be found bcter than washnig it in alcohol, as by allowing it to 

 dry with a little varnish in it, the hairs get a set, which preveiats 

 them from straggling, a point of uiuch importance. A few minutes 

 soaking in the lacker, will render it fit for use. 



We have repeatedly performed the jjrocesses above described, 

 and have now by us. articles which liave been lackered nearly 

 eighteen years, which have preserved their color, and apj)ear equal 

 to any similar work we have ever seen. [^Am, Mcch. Mag. 



TANNING. 



Tanning is one of those arts which depend on chemical princi* 

 pies, and may be considered as Chemico-mechanical. The basis of 

 the whole art, rests upon the combination of astringent matter, 

 with gelatinous, and changing it, from a substance, which is easily 

 dissolved or so!iibie in water, to one that is insoluble. 



Tanning is an ancient art. It has received many improvements 

 of late years, — is still undergoing improvement, and yet it may be 

 considered to be but little more than in its infancy. It presents a 

 fine field for scientific ingenuity and research, and we hope, that, 

 all engaged in the business, will strive to acquire theoretical, as well 

 as practical knowledge, and occasionally venture an experiment, 

 with a view of discovering some new principles, as well as to eluci- 

 date those that are old. We extract the following from Fyfe's 

 Chanislry^ with the hope of its being useful to some of the craft ; 

 who, although good tanners, may not perfectly understand tlie ra- 

 iionale of what they practise daily. 



When part of an animal substance, particularly sicin or cartilage, 

 is boiled in water, after having been previously well wa-^lied, a tluid 

 is obtained, which, when evapornted, and allowed to cool, con- 

 geals, forming a substance called Gelatin or Jellt/, If this he H*^^' 



