Edible Products. 



42 



January, 1909. 



of chalk and water; if this produces 

 an effervescence, more chalk must be 

 added to the main quantity, proceeding 

 cautiously and testing intervals, until 

 no effervescence is produced. A further 

 test is now made — a little of the mixture 

 is withdrawn and heated ; as soon as 

 bubbles of gas cease to be given off, 

 a few drops of acid (fresh lime juice 

 will answer) are added. This will pro- 

 duce a slight effervescence if chalk has 

 been added in right amount, and a brisk 

 effervescene if too much has been used- 

 In the latter case, more juice must be 

 added to the mixture and the process 

 of testing repeated.' 



If you add too little chalk to your 

 lime juice, you lose some acid. If you 

 add too much, it gives the manufacturer 

 trouble by wasting his sulphuric acid. 

 The buyers of citrate of lime have 

 determined to penalize anything con- 

 taining an excess of over 2 per cent, 

 of chalk. 



After neutralization, the citrate is 

 allowed to subside, and the mother 

 liquor is run off through a tap fitted 

 in the side of the vat. Hot water is 

 then run in and steam turned on to 

 thoroughly wash the citrate. The wash- 

 ing should be repeated several times, 

 the citrate being allowed to subside and 

 the water run off between each washing. 

 Finally it is agitated and run through 

 a lower cap into the filter bags to drain. 

 Afterwards, it is placed in a press to 

 extract as much moisture as possible, 

 and then at once conveyed to the drier. 



Recent experiments by Dr. Watts 

 show that the use of centrifugals is to 

 be recommended for removing the water 

 from citrate in place of the press. 

 Citrate can conveniently be washed with 

 a small quantity of hot water while 

 in the centrifugals, and when the mois- 

 ture has been removed by them, it can 

 be dried, in a much shorter time. 



When thoroughly dried, it should be 

 placed in a room to cool before being 

 tightly packed in barrels, hogsheads, 

 or puncheons for export. It is very im- 

 portant that the citrate be thoroughly 

 dried. If this is not done, much acid 

 may be lost. 



Citrate of lime when prepared in the 

 above manner is a white powder and 

 should contain about 64 per cent, of 

 citric acid. 



Citrate of lime is twice as bulky as 

 concentrated lime juice, but it is not 

 expected that freight on citrate will be 

 higher than on concentrated juice, as 

 shipping companies give a preference to 

 the dry over the liquid produce. 



The manufacture of citrate in Dominica 

 is as yet only in the experiment stage. 

 Probably many improvements will be 

 made in the process as time goes on. 



At present the great requirement is a 

 drying machine that will dry citrate in 

 a few hours without any loss of acid. 

 The driers chiefly in use now are modelled 

 on the cacao drier described in the 

 West Indian Bulletin (Vol. II, p. 173). 

 The process in this class of drier takes 

 too long, and the consumption of fuel is 

 too great, for the most economical pro- 

 duction of citrate. If centrifugals were 

 generally adopted and an improved 

 drier brought in use, the manufacture of 

 citrate of lime on large estates would be 

 considerably simplified. 



(To be continued.) 



SWEET POTATOES. 



(Continued from p. 51^8.) 

 Bedding the Seed. 



In the warmer portions of the sweet- 

 potato-growing district the seed should 

 be bedded when danger of frost has 

 passed. In the northern portion of the 

 area the seed should be placed in the 

 hotbed from the 20th of March to the 

 10th of April, after the temperature of 

 the bed has fallen to 80° or 85° F. and 

 become regular, 



If possible, select a warm, sunny 

 day for this work, in order that the 

 seed potatoes and the bed may not 

 become chilled. The soil to be used for 

 covering the potatoes should be sifted 

 beforehand and placed in piles in the 

 bed, where it will have become warm 

 and in good condition for use. Leaf 

 mould is pei haps the best material with 

 which to cover the potatoes, but where 

 this cannot be obtained a fine, rich, 

 sandy loam is the best substitute. 



Before placing the seed in the bed, an 

 inch or more of the finely sifted covering 

 material should he spread evenly over 

 the surface of the regular soil in the 

 bed. The potatoes are spread upon this 

 bed, each one being placed by hand so 

 that they will not touch, and about one- 

 half of the bed surface is covered. If 

 extra large potatoes are employed for 

 seed they may be split lengthwise and 

 placed with the cut side down in the 

 bed. When the potatoes are in place, 

 cover them to a depth of about 3 inches, 

 water by using a sprinkling can, and 

 then watch the temperature of the bed 

 carefully until the potatoes have formed 

 an abundance of sprouts. 



