Gums, ResinB, 



514 



[JtTKE, 190S. 



gether a disadvantage from an Indian 

 stand-point, because when everything 

 knowable about lac is revealed we shall 

 probably be favoured with a synthetic 

 article much on the same lines as syn- 

 thetic indigo and camphor, of which one 

 hears so much occasionally. 



The present method of converting lac 

 into what is known commercially as 

 shellac comprises three stages. In the 

 first the twigs, broken from trees and 

 containing lac incrustations, are crushed 

 in mills more or less archaic, and the 

 Avood and the bark are separated by 

 methods hardly less so. The granular 

 lac thus obtained — known in the trade 

 as "seed lac" — is submerged in water 

 for a day or more with frequent agita- 

 tion in order to extract the lac dye, 

 which, if allowed to remain, would 

 detract seriously from the value of the 

 finished shellac. This process is a tedi- 

 ous and unsatisfactory one, for no 

 amount of washing will remove the 

 whole of the dye from the lac, which in 

 consequence has to be sold at a figure 

 which is largely determined by the 

 amount of dye it contains. Attempts 

 have been made on many occasions to 

 overcome this difficulty by the use of 

 chemicals such as sodium carbonate and 

 borax; and, although these articles faci- 

 litated the extraction of the colour, they 

 did so much damage to the resinous con- 

 stituents of the lac that this process had 

 to be abandoned. In the third stage in 

 the preparation of shellac the washed 

 product is melted and strained while hot 

 through cloth bags on to the floor 

 beneath the fire, and is then stretched 

 into thin sheets, in which form the 

 highest grades of shellac are met with 

 commercially. There are, of course, 

 other grades of shellac which, owing to 

 .the impurities they contained, occupy a 

 lower level in the market and are not 

 always manufactured exactly on the 

 same lines or with the same amount 

 of care. 



Now if the laborious washing, whichj 

 even under the most favourable eircum" 

 stances, does not extract anything like 

 the whole of the dye, could be done 

 away with ; if the whole of the lac 

 produce of this country could be worked 

 up into the highest grade of shellac 

 with little trouble and cost, and if the 

 whole of the dye could be extracted 



leaving a pure shellac of the cleanest 

 quality, it seems reasonable to suppose 

 that a great impetus would be given to 

 lac industry in this country, and would 

 also tend to alter for the better the 

 conditions that now govern for the lac in- 

 dustry generally. Well, this point now 

 seems to have been reached, and parti- 

 culars of the new process by which the 

 desired end may be accomplished are to 

 be found in a Note on the Manufacture of 

 Pure Shellac, by Mr. P. Singh, F.c.s., 

 Acting Imperial Forest Chemist, just 

 issued in the Chemistry Series of the 

 " Indian Forest Memoirs," Volume I, 

 Part II. The process is said to be a very 

 simple and efficient one. It consists in 

 dissolving lac in methyl alcohol (wood 

 spirit), which treatment has been proved 

 to have the merit of completely dissolv- 

 ing out the resinous matter from the lac 

 leaving the dye undisturbed. The net 

 result is that lac of all grades, however 

 crude, may be rapidly converted into 

 shellac of the very purest quality. The 

 apparatus required is not costly and is 

 illustrated in the Note we are reviewing. 

 The only recurring expenditure appears 

 to be on account of the wood spirit 

 used ; but this, it is claimed, is not large, 

 as the bulk of the spirit is easily recover- 

 able for future use. To sum up, the chief 

 advantages claimed for the new process 

 are that every description of lac, 

 whether " coagulated," " phunki," or 

 otherwise, can be manufactured into 

 pure shellac ; that the washing difficulty 

 is completely overcome ; that the neces- 

 sity for mixing rosin with seed lac for 

 the purpose of facilitating the refining 

 process is avoided ; that an increased 

 yield of shellac is obtained : that the 

 shellac made is much finer and purer 

 than in the case of the old method ; that 

 less labour and expenditure are involved, 

 and that the highly refined character of 

 the new shellac will ensure a ready sale 

 and higher price in the world's markets 

 and particularly in the United States, 

 where the introduction of the free 

 alcohol law, it is said, has led to the 

 increased consumption of shellac. At 

 all events, Mr. Singh's Note is bound to 

 command the earnest attention of the 

 lac trade, and we may add that copies of 

 it may be obtained from the Superin- 

 tendent of Government Printing, India, 

 8, Hastings Street, Calcutta, at the 

 moderate price of 8 annas each. 



