October, 1912.] 



299 



come to about Rs.3-12-0, five pairs of cattle being required. The same 

 work can be done with a 3 H.-P. engine and a double 6 in. pump in about 

 eight hours. The fuel for the engine will cost annas 12 a day and the 

 other expenses, including driver's wages and 12^ per cent, for interest 

 and depreciation, will make the total slightly under Rs. 2 a day ; that is 

 to say, the cost of irrigation will be reduced by Rs. 1-14-0, equivalent to 

 at least Rs. 375 in a year allowing for only 200 working days, and assuming 

 that the cattle can be usefully employed on other work during the rest 

 of the time. Now a saving of Rs. 375 capitalised at t>i per cent, amounts 

 to Rs. 6,000, but the cost of an engine and a pair of these pumps on a 

 30 ft. lift is Rs. 1,535 in Madras, aud in most places they could be provided 

 with an engine house and erected at the site of the well for less than 

 Rs. 2,000 ; that is to say, there is a clear saving in the transaction equi- 

 valent to 6| per cent, on Rs. 4,000 a year. The value of a well is not what 

 it will cost to sink, but depends upon the quantity of water which it 

 will yield, and no matter what it is worth to start with, its value is 

 increased by Rs. 6,000 if the cost of lifting water is reduced from Rs, 3-12-0 

 to Rs. 1-14 0. 



DR. SCHIDROWITZ ON RUBBER LATiCES. 



Chemical and Physical Properties. 

 Dr. Philip Schidrowitz delivered the second of the special series of 

 lectures on Rubber arranged by the Imperial College of Science and 

 Technology in the Chemistry- Lecture Theatre of the Royal College of 

 Science. The lecture dealt with the chemical and physical properties of 

 rubber latices, with the theory and practice of coagulation, and, finally, 

 with the commercial preparation of various types of crude rubber. The 

 lecturer pointed out that no single theory could be formulated which 

 would cover all the remarkable phenomena attending on coagulation, the 

 reason being that latices from different species varied most markedly in 

 regard to their physical and chemical properties, and even within the 

 same species considerable essential differences occurred. These facts 

 were of very great practical impoi * . nee, and the neglect to appreciate 

 them in the past had been the cause of the loss of much time and money. 

 Even now, the facts were not fully grasped by many of those eng?„ged in 

 the plantation industry, and the result was a greater variability in 

 regard to quality than was either necessary or desirable. Much work 

 remained to be done before it would be possible to state with certainty 

 that the Plantation manager could produce from any given batch of latex 

 the best possible result in regard to quality and quantity of rubber, but 

 considerable progress was being made, and students of the Royal College 

 of Science would be glad to hear that good work was being done on the 

 plantations in this direction by several gentlemen now graduates of this 

 College and but lately their fellow students. A fair proportion of planta° 

 tion rubber was, in his opinion, already superior to any other rubber 

 produced, not excluding " fine hard " Para, and there was very little doubt 

 that at no very distant date it would replace the latter as the standard 

 of quality. As chemist, Dr. Schidrowitz thought they might be parti- 

 cularly interested in the high grade rubber produced by a chemical pro- 

 cess from a very low grade raw material— namely, jelutong. Specimens 

 of the latter, as well as of various grades of plantation rubbers, crude 

 rubbers, aud of latices, were shown, and the lecture was further illus- 

 trated by lantern slides.— The Rubber World. 



