43 



dian Bulletin, Vol. II., p. 309, which briefly is this : ' Carry on the 

 concentration until the citrometer, when immersed in the juice at 

 the boiling temperature shows a density of 66°.'* 



A much finer product would be obtained if the juice were con- 

 centrated in steam-heated pans instead of over open fires. It is 

 suggested that shallow wooden vatsheated by steam coils of copper 

 or block tin will serve for this purpose. I have not seen such ap- 

 pliances in use, but the suggestion is one well worthy of consider- 

 ation and should commend itself to planters for trial. 



I am informed that there is a demand for the better qualities of 

 concentrated lime juice for direct use in various arts and manufac- 

 tures in the place of crystallised citric acid. This is of import- 

 ance, for, if a fine quality of concentrated juice, of good colour, 

 and free from suspended impurities can be placed on the market, 

 it is reasonable to suppose it will be in demand for those purposes 

 in which a solution of citric acid can be employed in place of the 

 crystallised acid, and should command a higher price than ordi- 

 nary concentrated juice. 



ADDENDUM. 

 THE USE OF CENTRIFUGALS FOR DRYING CITRATE. 



Until recently I was of opinion that it was sufficient to press the 

 wet citrate in bags in order to remove the superfluous water before 

 putting the citrate in the drier. I have, however, recently had an 

 opportunity of conducting some experiments with citrate, as pro- 

 duced on a commercial scale, and have ascertained that a centri- 

 fugal will remove a considerable quantity of water from citrate 

 which has already been well pressed. 



The experiments were conducted with a model centrifugal hav- 

 ing a basket 5 inches in diameter and run at a speed of about 

 3,000 to 3,500 revolutions a minute ; thus developing a centrifu- 

 gal force of about the same intensity as that obtained in large 

 centrifugals in commercial use. 



The experiments also demonstrated very clearly that citrate 

 can be handled very conveniently by means of centrifugals. The 

 centrifugal employed for the experiments was lined with twill 

 cloth, of the kind used for press cloth. There was no tendency 

 for the citrate to force its way through the cloth and the water 

 was removed with striking rapidity. The centrifugal removed 

 a considerable quantity of water from citrate which had already 

 been well pressed. 



The citrate may be washed very conveniently in the shortest 

 space of time and with the minimum amount of hot water while it 

 is still in the centrifugal, thus producing a pure citrate of good 

 colour. 



It has frequently been noticed that citrate dries with difficulty 

 when it has been so handled as to produce a plastered surface on 



Citrometers may be obtained from Messrs. Baird and Tatlock, 14 Cross Street 

 H itton Gardens, London, W.C., Messrs J. Long & Co., Eastcheap, London, E.C. or 

 from most dealers in chemical apparatus. 



