Field Experiments on Swedish Turnips. 
93 
quarter-acre separated from the adjoining one bj a path 2J feet 
in width. 
The land was bouted up on the 5th of May, horse-hoed on 
the 17th of May, ploughed back May 18th, horse-hoed June 21st, 
and set out June 23rd, 1880. It was then in a fairly clean 
condition, but brought to light afterwards a great many surface- 
weeds, which were kept under by horse- and hand-hoeing as 
well as the wet weather in July would permit. 
The soil of the experimental swede-field is much stronger, 
and contains more clay than Stack-yard field, upon which the 
experiments upon the continuous growth of wheat and barley, 
and the rotation-experiments, have been in progress for the last 
four years. 
The surface soil, to the depth of 18 inches, contains a fair 
admixture of sharp sand and clay ; it may be briefly described 
as a rather strong turnip-loam. It rests on a reddish coloured, 
and in places dark coloured, retentive clay subsoil. 
A preliminary examination showed that the soil contains 
about 1 per cent, of carbonate of lime, and an appreciable 
amount of phosjihoric acid and potash. I am at present 
occupied with careful detailed analyses of a number of samples 
taken in Warren-field at different depths, at places upon which 
none of the manures used were put. On a future occasion I 
hope to report the results of these soil-analyses, and also upon 
the composition and nutritive value of the swede-crops grown on 
the various experimental plots. 
The primary object of the experiments was to test the effects 
of finely-ground coprolites, and of superphosphate made by 
treating coprolites with sulphuric acid. 
At the same time it was considered desirable to try experi- 
mentally the fertilising properties of ground raw bones and 
dissolved bones, and also the effects of precipitated phosphate of 
lime — a commercial material which is obtained as a by-product 
in the manufacture of glue from bones, and which may be 
regarded as the mineral portion of bones, in a chemically 
divided or precipitated form. In this condition, the mineral 
portion of bone, consisting mainly of tribasic phosphate of lime, 
is infinitely more bulky and more minutely divided than bone- 
ash, ground into the most impalpable powder. 
Redonda phosphate, a mineral consisting of hydrated phos- 
phate of alumina and iron, and unsuitable for the manufacture 
of superphosphate, or similar artificial manures, in a finelv 
ground condition, has been recommended as a manure from 
time to time, but I am not aware that it has ever been tried in 
exact field-experiments. Last spring, Redonda phosphate was 
offered for sale at 21. to 21. 5s. a ton, and, on account of its cheap- 
