34 farmers' and mechanics' journal. 



stick-lac, seed-lac. and shell-lac. The former consists of the resin 

 attached to the twigs, the seed-lac is the substance separated fronn 

 the wood, the shell-lac is in the form of thin lamina, or plates. 

 Lac in its native state, contains a considerable quantity of coloring 

 matter, of which it is nearly deprived, before it is exported, as it is 

 employed in India, for giving a beautiful red, and some other tints, 

 to cotton, and other goods. 



In the application of Lac to the purpose of varnishing, we shall 

 confine our observations to seed-lac, and shell-lac ; and as the lat- 

 ter is the kind most extensively employed, we shall consider it first. 

 The books inform us, that shell-lac consists of the seed-lac puri- 

 fied, fused, and run into thin plates. 'J here is, however, sufficient 

 reason to doubt the correctness of this statement, as the shell-lac 

 is much cheaper than the seed-lac, is more fusible, much more 

 easily dissolved in alcohol and forms a softer varnish ; it is highly 

 proi)al)le. therefore, that shell-lac contains a considerable portion 

 o^ some cheaper resin, with which the lac is fused, at the time of 

 its formation. 



ShcU-lac Varnish. — In making spirit varnishes, it will be found 

 that the resin to be dissolved, may be from one-third to one-fourth 

 of the weight of the alcohol employed ; a complete solution of a 

 larger quantity cannot be eirecled ; and some of the resins used are 

 much less soluble than this. The best shell-lac, is that which is 

 most transparent, and which has the greatest brilliancy of surface. 

 Its hardness is also a good test ; of two portions, that which is least 

 easily scratched with the point of a knife, may be considered as the 

 best. To every pint of alcohol, from three to four ounces of shell- 

 lac may be added ; glass bottles are generally employed for contain- 

 ing the mixture, but vessels made of tin are much to be preferred, 

 for very obvious reasons. The shell-lac ought not to be pulveriz- 

 ed, but may be put into the spirits, in pieces as large as the vessel 

 will admit. In warm weather it is not necessary to place it near a 

 fire, as it will, if frequently shaken, dissolve in the course of a day. 

 Frequent shaking is of importance in making this, and many other 

 varnishes, as the resin will otherwise agglutinate into one mass, and 

 will be afterwards dissolved with difficulty. In cold weather the 

 bottle may be placed near a fire, so as to keep it slightly warm ; if 

 much heated, there will be a considerable loss of alcohol, by evapo- 

 ration ; there should be a small notch cut the whole length of the 

 cork, to allow the escape of vapor, when placed near the fire, other- 

 wise the cork may be blown out, and if too close to the fire, com- 

 bustion may be produced. Those who make spirit varnish in the 

 large way, use a barrel churn, into which the materials are put, and 

 they are agitated until the whole of the resin is dissolved. This is 

 an excellent mode, as there is no loss from evaporation, and the 

 resin is prevented from agglutinating. Shell-lac varnish is never 

 perfectly clear, as the resin contains some matters not soluble in 

 alcohol ; when the lac is dissolved without heat, the greater part 

 of this remains at the bottom, but if made pretty warm, it is diifus- 

 ed in clouds through the whole mass, nor can it be separated by 



