Mr. Hughes (/oc. cit., p. i56) analysed 27 samples of the shales actually 
used for manures, the average content of Nitrate of Soda in the samples being 
6.7 0/0, or if six were excluded as not representing the bulk of the material 
now used, 8./1 0/0. (See Table n° 1 , p. 169.) 
A further set of analyses were made by the Imperial Institute, London, for 
the Egyptian Ministry of Agriculture. The nitrate shales selected were from 
the Qena district, and the report by Professor Dunstan is given in The Agri- 
cultimd Journal of Egypt, vol. II, Part II, 1 f) i 2 , p. 89 et seq. The percentages 
in tabular form of the principal salts present are given in Table n° 2, p. 169. 
SUMMARY. 
Taking the averages of all typical analyses recorded, a mean content of between 
5 ojo and 6 ojo nitrate in the shales is obtained. 
II 
EXPERIMENTS IN METHODS OF ENRICHMENT IN NITRATES. 
The following are the most interesting efforts in this direction carried out 
up to the present. 
Four tons of shale were washed at Mex by Mr. A. H. Hooker, then Controller 
of the Government Salt Department, and yielded 2.2 0/0 of total salts, of 
which 67.3 0^0 (i. c. 1 .68 0^0 of the whole) was Sodium Nitrate. 
Mr. Floyer also made experiments and found rcthat by one extraction with 
ft cold water he was able to obtain a solution of salts which on evaporation 
ffgave a mixed residue of nitrate, chloride and sulphate, containing some 
rr/i/i 0^0 of Sodium Nitrate n (Hughes, loc. cit., p. 157). 
Subsequently Mr. Floyer carried out a series of experiments at Mualla 
(28 kilometres above Armant, on the right bank). These were completed early 
in 1895, and were the subject of a report presented to the Ministry of Public 
Works, a co])y of which was appended to a paper by the same author read 
