136 CHEMICAL COMPOSITION OF KARROO ASH. 



a long stretch of years in the Government Chemical Laboratory 

 in Cape Town. The object of those investigations was not to 

 ascertain what kind of an ash may be produced in the laboratory 

 from a manure that originally might have been either excellent 

 or poor, but to gain reliable information with regard to the 

 usual composition of Karroo ash as prepared, from start to 

 finish, by the farmer and his men, on the farm. 



It was as long ago as 1890 that the first steps in this investi- 

 gation were taken. Samples of Karroo ash were obtained, 

 during that year, from the neighbourhood of Grahamstown, in 

 the Albany Division, from the farm Tafelberg, in the Division 

 of Middelburg. and from Victoria West, and in these samples, 

 numbered respectively i, 2, and 3 in Table I, appended to this 

 paper, determinations of potash and phosphorus pentoxide were 

 made. Reference to the table will show at once that the Albany 

 sample was very impure, and practically worthless as a fertiliser, 

 and that from Victoria West somewhat better, though also very 

 impure, while the Tafelberg ash was of excellent quality. In 

 1893 information was received that a ([uantity of kraal manure 

 ash was being ofi^ered for delivery at Fraserburg Road Station, 

 at a cost of £3 15s. per ton. A sample of this ash (No. 4) 

 was procured and analysed, and was found to be equal in ([uality 

 to the average ash afterwards obtained by Mr. Croghan in his 

 laboratory from Cape Province kraal manures. In addition to 

 its plant-food constituents, it contained about 13 i)er cent, of 

 common salt (-7.91 per cent, of chlorine) and a good deal of 

 carbonate of soda, so that it would have had to be used with 

 great caution on lands exhiljiting a tendency towards " brack " 

 or " alkali." It was probably with reference to lands of such 

 a character that a farmer once wrote to the Cape Agricultural 

 Journal : " Where I spread kraal manure ash only ' ganna ' and 

 ' brakbosjes ' thrive."* 



During 1895 a sample of raw — i.e., unburnt— kraal manure 

 (No. 5) was procured from the Victoria West Division, and, 

 although better than that previously analysed, it still showed 

 the defect of a large admixture of earthy material. The sample, 

 as received in the laboratory, contained 37.42 per cent, of water. f 

 Analysis of the ash showed that the sample was a manifest 

 improvement on that previously examined from the same Divi- 

 sion, though evidently, capable of further purification from sand 

 and earth. 



In 1896 three more samples of kraal manure ash were 

 examined, two of these again from the Divisions of Fraserburg 

 and Victoria West, and the third from the Prince Albert Divi- 

 sion. The first two (Nos. 6 and 7) showed a most excellent 

 advance on the previous analyses, but the Prince Albert sample 

 (No. 8) was only partially analysed, on account of the large 



* C.G.H. Agric. .fourii. (igoT,). 23. 240. 



t It is obviously uneconomical to transport a manure with so high a 

 water content as this. 



