If a standard of 2 lbs. per gallon is adopted, the formula given for the 1-1/2 lbs. standard will not give full satisfaction, and the quantity of acid solution must be increased slightly in order to obtain complete coagulation. Assuming that the original solution is prepared in 1 per cent. strength, the following difference would be noted: (_a_) One part pure acetic acid to 100 parts water (theoretically 99 parts). (_b_) _1-1/2 lbs. per gallon._ | _2 lbs. per gallon._ | Of the above solution use 1 gallon | Of the above solution use 1 to every 12 gallons of standardised| gallon to every 10 or 11 latex. | gallons of standardised latex. It is not possible to lay down an exact figure governing all cases, as so much depends upon the treatment undergone by the latex before it reaches the store. Some estates continue to use solutions of greater strength, generally 5 per cent., in crepe preparation. While such solutions may be effectively stirred in when the latex is dilute, it is advised that for intimate mixture the solution need not be stronger than 1 per cent. In estimating the quantities of acetic acid required much depends upon the interval which is to elapse between the addition of acid and the time of working of the coagulum. If the rubber is to remain until next morning, the average formulæ will be found suitable; but if it is required to work the coagulum with an interval of less than three hours, an excess of acid must be employed. The excess need be comparatively small, unless the interval is much reduced. For instance, it is the practice on some few estates to begin the machining of the coagulum about half an hour after coagulation commences; in which case it is usual to add from a quarter to a half of the normal quantity in excess. It need scarcely be pointed out that unless this procedure is strictly unavoidable it should be discouraged on account of the waste of coagulant involved. Incidentally, the use of strong solutions of acid under such circumstances may lead to increased deterioration of the rolls. COLOUR OF FINE CREPE.--We are sometimes assured that manufacturers do not pay the attention to the question of colour which sale conditions would lead one to believe. As far as we are concerned, and as long as there is no direct traffic between producer and consumer, it must be recognised that in the vast majority of cases we are forced to concern ourselves only with the standards set up in the markets. This, in spite of the knowledge that, all other things being equal, the arbitrary distinctions in colour afford no indication of the intrinsic value of the rubber. Under present circumstances it is plain that if paleness is demanded it has to be supplied. Probably without exception all estates employ sodium bisulphite as the agent for the prevention of that darkening (oxidation) which is natural in drying rubber.