Assuming we commence by making up our stock solution of acid by adding 100 parts of water to 1 part of pure acid, this gives us a mixture of 1 to 100. For 1 gallon of pure latex it would be necessary to add one-tenth of its volume of the above mixture--_i.e._, 16 ozs. Suppose we take a gallon of pure latex and add a gallon of water, we now have 2 gallons of so-called latex. But we still have only 1 gallon of real latex present in the diluted latex, and it is only necessary to add sufficient acid to coagulate this gallon--_i.e._, 16 ozs. Further, if 1 gallon of latex be diluted with 2, 3, or even 4 gallons of water it is still only necessary to add 16 ozs. of the acid mixture. At dilutions beyond this limit, however, it is necessary to add a little more acid to obtain complete coagulation. In the process of preparing sheet rubber it is very necessary to see that the minimum quantity of acid is used, otherwise visible defects are caused. But in coagulating latex intended for preparing crepe, where the rubber undergoes protracted washing on the machines, the presence of a slight excess of acid in coagulation is not calculated to cause any deterioration in the quality of the rubber. Advantage must not be taken of this statement to argue that more than a slight excess may be used without injury to the rubber, as it can be shown that the use of a large excess of acid results in an inferior rubber. QUANTITIES NECESSARY FOR MODERN REQUIREMENTS.--It may be commended to the notice of the beginner that any further experimental work as to the quantity of acetic acid necessary for complete coagulation would only involve a waste of time and energy. The general figure given in a preceding paragraph (1 part pure acid to 1,000 parts of latex) may be accepted as the rough basis for working. In modern practice, however, undiluted latex is usually diluted to a standard which may vary on different estates from 1-1/4 lbs. to 1-1/2 lbs. dry rubber per gallon. Latices of these strengths can be coagulated at a ratio of 1 part pure acid to 1,200 parts of standardised latex; and this quantity need not be exceeded, except in cases where an appreciable amount of some anti-coagulant is present in the latex. The proportion may then be raised to 1 in 1,000.