191 1.] Summary of Agricultural Experiments. 593 



quite unsuitable for use on the land, as, on being wetted, it 

 would tend to set like cement. It is doubtless unusual for lime 

 having so large a content of silica to be sold for agricultural 

 use, as purchasers would readily detect its unsuitability for 

 slaking, but farmers would be well advised when buying this 

 material to ask for a statement as to the amount of siliceous 

 matter present. In purchasing burnt lime, quicklime, lime- 

 shells, or caustic lime (all terms for one and the same material), 

 a guarantee should be obtained that it contains not less than 

 85 per cent, of pure lime (CaO) and not more than 4 per 

 cent, of magnesia (MgO). It may be noted in this connection 

 that the expressions pure lime, oxide of lime, oxide of 

 calcium or calcic oxide, sometimes made use of by sellers of 

 lime, all have the same meaning. Ground lime consists of 

 burnt lime ground to a fine powder, and should be similar 

 in quality to quicklime. Ground limestone, on the other hand, 

 is limestone rock — that is, more or less pure carbonate of 

 lime — ground to a fine powder. When the purer limestones 

 are used for this purpose, the percentage of carbonate of lime 

 may be expected to exceed 95 per cent. The Board's leaflet 

 No. 170, on The Uses of Lime, may be obtained free of charge 

 and post free on application. 



SUMMARY OF AGRICULTURAL EXPERIMENTS.* 

 Soils and Manuring. 



The Lime in Basic Slag (Jour. Soc. of Chem. Industry, Vol. 30, 

 No. 9, May 15, 1911)- — In a paper by Mr. James Hendrick in the 

 Journal of the Society of Chemical Industry in 1909, it was shown 

 that there is a much smaller percentage of free lime in basic slag 

 than is commonly represented, and that calcium carbonate is prac- 

 tically absent. At the same time, it was shown that there is a con- 

 siderable amount of "lime available as a base," that is, lime capable 

 of neutralising acidity in the soil and of acting- as a base during 

 nitrification. An attempt was made to measure the available base 

 m basic slag, chiefly by distilling a solution of ammonium sulphate 

 with the slag and estimating the basicity from the amount of ammonia 

 given off. Ammonium sulphate was chosen on account of its being 

 extensively used as a fertiliser. It undergoes nitrification in the soil, 



* A summary of all reports on agricultural experiments and investigations 

 recently received will be given each month. The Board are anxious to obtain 

 for inclusion copies of reports on inquiries, whether carried out by agricultural 

 colleges, societies, or private persons. 



S S 



