t 559 1 



jailor to the using of bones, ashes, and mustard-cake were 

 applied, after the plants were dug up all round. Phosphates 

 also have the power -of intensifying flowering and fruiting 

 tendencies of plants. Hence the advice of applying bones 

 also. The application of ashes resulted in profuse formation 

 of lime fruits that very year. 



(3) It has been noticed that tobacco leaves charged with 

 potash salts of vegetable acids burn readily, and in a manner 

 quite different from leaves containing an excess of chlorides. 

 Hence -Potash salts (not in the form of chlorides but in that 

 of nitrates and sulphates) have been found very appropriate 

 manures for cigar-making tobacco. The presence of much 

 carbonate of potash in tobacco ash, is an indication that 

 considerable quantities of organic compounds or nitrate of 

 potash are confined in the leaves. When subjected to heat 

 the organic potash salts swell up so that the charcoal is left 

 in a spongy, easily combustible condition such as we see 

 when a e;ood cigar is burning, the ultimate product of combus- 

 tion being carbonate of potash. 



914. Estimation of available phosphoric acid and 

 potash. Soils are ordinarily analysed for the estimation of 

 the total Nitrogen, phosphoric acid, potash and lime, there 

 are in them. For the estimation of available phosphoric acid 

 and potash, a fairly satisfactory method has been devised by 

 Dr. Dyer of London. A weight of air-dried soil correspond- 

 ing to 200 grammes of completely dry soil is taken, and 

 treated in a Winchester quart bottle with 2 litres of distilled 

 water, in which 20 grammes of pure citric acid had been 

 dissolved (i.e., with 2 litres of I per cent, solution of citric 

 acid). The soil is left in the solution for a week, during 

 which time it is frequently agitated. At the end of this 

 time the solution is filtered, and a portion of solution 

 corresponding to 50 grammes of soil is taken for the deter- 

 mination of dissolved potash and a like quantity for the deter- 

 mination of dissolved phosphoric acid. The filtrates are evapo- 



