358 SoIL ANALYSIS. 
extraction is made sufficiently long to minimise errors 
due to variations in the actual time, the strength of the 
acid, or the temperature. Unignited soil is taken, since 
ignition effects a drastic and variable alteration of the 
constitution of the soil—e.g. no constant proportion is 
found between the potash extracted from ignited and 
unignited soil. Hydrochloric acid is taken as the most 
generally effective solvent; even peaty soils are found to 
yield as much phosphoric acid to hydrochloric acid as to nitric 
acid, or aqua regia. 
(9) Determination of <Avatlable Phosphoric Acid and 
Potash.—Unless otherwise specified, Dyer’s method shall be 
followed, the quantities used being 200 gms. unground fine 
earth, and 20 gms. citric acid in 2,000 c.c. water, no further 
addition of citric acid being made. 
(10) Expression of Results. — Unless otherwise stated, 
results shall be expressed as percentages calculated on the 
fine earth in an air-dry state. 

ADULTERATION OF FOOD IN 1899. 
Ihe report of the Local Government Board for the year 
1899-1900 contains particulars of the results of the analysis of 
samples of food and drugs taken by the local authorities in 
1899 under the powers conferred on them by the Sale of Food 
and Drugs Act, 1875. The total number of samples 
examined by the public analysts amounted to 53,056, or one to 
every 547 of the population of 1891, and about 3,500 more than 
the number taken in 1898. In London nearly twice as 
many samples are obtained in proportion to the population as 
in the provinces—viz., one for every 325, as against one for 
every 619 persons outside the metropolis. No sample was 
taken in the county of Radnor, orin the boroughs of Congle- 
ton, Penzance, Glossop, Barnstaple, Louth, Kendal, and Tyne- 
mouth. Within the jurisdiction of six counties and seven 
