1836,] On the solidifying, or induration of Chunam. 100 



Suggested — that a piece of well burnt brick, say three in- 

 ches square be taken, and ascertain what degree of weight it 

 -Will require to crush it. Take another piece of brick of similar 

 dimension, and let it be weighed, — let it remain immersed in 

 a solution of lime and water for 24 hours — take it out, let it 

 dry for a month or more, then weigh it — ascertain what it has 

 gained in weight— and try what force it will require to frac- 

 ture it as in the preceding. 



Take a third piece and weigh it — then immerse it in a so- 

 lution of jaggery water, to w hich lime has been added — and 

 which has dissolved as much lime as it is able ; let it remain 

 24 hours, take it out and let it dry well for a month or longer, 

 weigh it — and then subject it to pressure — and ascertain whe- 

 ther it will fracture at a less or greater weight than the 

 other. 



Take an ounce of worked up chunam without jaggery — - 

 expose it to the open air until dry — put it into a retort—add 

 muriatic acid, apply the retort to a receiver over the pneuma- 

 tic trough, see what quantity of carbonic gas comes over. 



Take a similar quantity worked up with jaggery water, let 

 it dry for a week or longer and do the same with it as the 

 preceding— these experiments will shew which is carbonated 

 the soonest and the most. 



Note, —The ingenious writer of the foregoing paper has taken op a 

 subject which is well deserving notice and further investigation; and 

 in connexion with it might be investigated the causes of the decay of 

 modern brick and chunam masonry, compared with the hardness and 

 durability of w ork executed 50 years ago, The use of jaggery in 

 chunam is frequently set aside when buildings are executed by the 

 Engineer's department j we should be glad to be favoured with the de- 

 tails of any experiments that have been made, tending to shew the 

 grounds of this new usage. From a few experimental facts within our 

 own knowledge we are inclined to believe that this departure from na- 

 tive practice is not to be commended. — J. B. 



