224 JOURNAL, R.A.S. (CEYLON). [VOL. II., PART II. 



As regards filters, having remembered seeing, when the 

 coolies poured out the chatty of water round the cocoanut 

 plants, that all the vegetable impurities seemed to remain 

 on the surface of the sandy soil, the idea of a sand filter 

 occurred to me. In a box filter of fine wire cloth I spread 

 three inches of sharp sand from the bottom of a well, 

 and poured on gently the liquor to be filtered. The sand 

 stopped even the most minute particles, and the liquid 

 came through quite limpid. These sand filters acted in 

 the most perfect manner possible so long as mundi 

 was present,— it preventing, in some curious way, the fine 

 particles of lime from choking the sand ; but having lately 

 tried them with the liquor which contained none, they failed 

 of their effect. They still stop every impurity, but soon get 

 choked, and are thus too slow for practical purposes. But 

 cane juice which has been defecated passes through well, and 

 therefore I recommend a trial of these sand filters to sugar- 

 makers. I noticed in this trial that the lime which 

 remained in the liquor was taken up and dissolved by the 

 sugar when the density of the syrup was about 20° Beaume. 



In the next trial, the floating lime was taken out with 

 the white of an egg to two gallons. Eggs are not generally 

 admitted as legitimate materials for defecation, as not always 

 procurable, but in a country where this would only add 

 one-sixteenth of a penny to the value of a pound of sugar I am 

 not so sure that they might not be occasionally employed. 

 In this case they took every atom of lime out, and the result 

 was an excellent sugar, the grain of which I purposely 

 " broke " for claying,* and it is the clayed sample No. 4. 

 Thus I came to the conclusion that lime, merely in solution, 

 does not make the sugar dark, and only injures the result by 

 forming an undue quantity of molasses. And yet all the 



* An operation the use of which is now quite exploded, or ought 

 to be. 



