1829.] Queries respecting the Manufacture of Caoutchouc. 305 . 
Tirahut. It is scraped as usual, and collected at the furnace- A little rice 
straw is first placed on the ground, and covered with the saline earth to about 
four inches in thickness. The straw is then burned ; and the burnt matter is co- 
vered with a foot of straw, and that by four inches of saline earth, when this 
straw also is burned ; and the same is repeated seven times ; after which the heap 
is covered with some fire wood, which is burned. The burnt saline matter 
(Bani) is then put into a cistern of clay, and about three thousand seers, or six 
thousand pounds of water are poured upon it. Next day the workmen take out 
the uppermost part of the matter, which had been put into the cistern, aud from 
whence this water has washed the saline parts, and add as much more water; and 
this is repeated again and again, until all the salt has been extracted, and nothing 
remains in the cistern but brine. This is then allowed to flow from a cock, and 
is evaporated in from thirty to forty earthen pots, placed in a row over a trench, 
which serves as a furnace, the fuel being put in at one end, and the smoke coming 
ont at the other. The evaporation is carried to dryness, but the khari’ turns out 
of three different qualities, which is attributed to circumstances in the burning, 
that are beyond the control of the operator. When the operation has succeeded 
well, they procure a whitish salt in grains, which is called phul khari’, and that is 
given to cattle. It sells at eighty-eight seers (seventv-two sicca weight,) or pounds 
one hundred and seventy-eight "and a quarter for the rupee; when the operation has 
less success, a more impure salt called sinrler khari is procured, and is used in 
the preparation of red lead. It is sold at ninety-six seers for the rupee. When the 
operation is least successful, a very black salt is procured in a solid mass. It is 
called chamari khari, being used by tanners, and sells at one hundred and twelve 
seers for the rupee. All these I have refined into a very fine purging salt, which 
in its crystals entirely resembles Glauber’s salt, but its taste is not near so 
strong nor disagreeable : and I would recommend, that the Commercial Resident 
should be directed to prepare, a quantity sufficient for the Hospitals. It would 
come much cheaper than the purging salts imported from Europe, and is not in- 
ferior in quality to the best of them. Should he be doubtful of skill to conduct 
the process, he might send a quantity of the crude salt to the Company s Apothe- 
cary at Calcutta, by whom the operation would be, no doubt, more properly con- 
ducted.” 
IX Queries respecting the Manufacture of Caoutchouc. 
We have been requested by a friend to give insertion to the following queries, 
which have been drawn up, we believe, by some one connected with the manufacture 
of water proof cloth in England. We need not point out to our readers the great 
utility that may be the result of auy information they are capable of communi- 
cating. 
What are the trees which yield Caoutchouc ? . , 
Is it produced from any other genera of plant besides Hevea (as It. guxmumiff) , 
Euphorbia (as E. punier a), Urceola (as V. elastica), Jatropha (J elast.ca*), Ecus 
(various species of) ? Are there not certain species of plants which yield caout- 
chouc of a much better quality than others ? The former yielding a caoutchouc which 
remains permanently tough and clastic, though kept for any length of time ; the 
latter, yielding one which approaches more to the nature of glue or birdlime, 
than of good caoutchouc ; or which, although sufficiently tough and elastic, when 
newly prepared, gradually undergoes decomposition upon being kept, becoming 
soft and glutinous, or becoming converted into a brittle substance having some- 
what the appearance of rosin ; or which becomes soft and adhesive like pitch, and 
remains permanently so, on the application of a very moderate heat 
Does not the Urceola elastica generally yield caoutchouc of the best quality. 
Is not the caoutchouc obtained from the Hevea gmanensis y also of tolerably good 
' |U i'"notthe caoutchouc obtained from the different species of Ficus which yield it, 
universally of bad quality, being soft and clammy, and easily destroyed even by a 
gentle heat? 
* The Hevea guianensis and Jatropha elastica are one and the same plant j and 
both names have been changed for Siphonia elastica, Ed, 
