230 Appendix 



follows: 200 grams dry soil are placed in a Winchester quart bottle 

 with 2 litres of distilled water in which are dissolved 20 grams of 

 pure citric acid. The soil is allowed to remain in contact with the 

 solution at ordinary temperatures for seven days, and is shaken a 

 number of times each day. The solution is then filtered, and 500 c.c. 

 taken for each determination; this is evaporated to dryness, and 

 gently incinerated at a low temperature. The residue is dissolved 

 in hydrochloric acid, evaporated to dryness, redissolved, and filtered ; 

 in the filtrate the potash is determined as above. For the phosphoric 

 acid determination the last solution is made as before, with the nitric 

 acid; then proceed as above. 



Mechanical analysis. 1. Ten grams of the air-dry earth, which 

 has passed a 3 mm. sieve, are weighed out into a porcelain basin 

 and worked up with 100 c.c. of is/5 hydrochloric acid, the acid being 

 renewed if much calcium carbonate is present. After standing in 

 contact with the acid for one hour, the whole is thrown upon a dried, 

 tared filter and washed until free of acid. The filter and its contents 

 are dried and weighed. The loss represents hygroscopic moisture and 

 material dissolved by the acid. 



2. The soil is now washed off the filter with dilute ammoniacal 

 water on to a small sieve of 100 meshes to the linear inch, the portion 

 passing through being collected in a beaker marked at 10, 8-5 and 

 7-5 cm. respectively from the bottom. The portion which remains 

 upon the sieve is dried and weighed. It is then divided into "fine 

 gravel" and "coarse sand" by means of a sieve with round holes of 

 1 mm. diameter. The portion which does not pass this sieve is the 

 "fine gravel." This should be dried and weighed. The difference 

 gives the "coarse sand." If required, both these fractions can also 

 be weighed after ignition. 



3. The portion which passed the sieve of 100 meshes per hnear 

 inch is well worked up with a rubber pestle (made by inserting a glass 

 rod as handle into an inverted rubber stopper), and the beaker filled 

 up to the 8-5 cm. mark and allowed to stand twenty-four hours. The 

 ammoniacal liquid which contains the "clay" is then decanted oft' 

 into a Winchester quart. This operation is repeated as long as any 

 matter remains in suspension for twenty-four hours. The liquid 

 containing the "clay " is flocculated with hydrochloric acid. The dried 

 residue consists of "clay" and "soluble humus." After ignition the 

 residue gives the "clay" and the loss on ignition the "soluble humus." 



