It would be out of place here to enter into the various 

 questions involved, such as the cost of evaporating the 

 solution of nitrate of soda and other salts which would 

 be obtained by treating tafia with water, but we may 

 state that the relative poverty of the material does not 

 hold out much hope that the process could be profitably 

 conducted. 



From calculations which were made it appears that the 

 cost of transport amounted to an equivalent of about Lst. 5 

 per ton for nitrate of soda though at present it probably 

 amounts to more. There can be no doubt that the use of 

 the commercial material would save a considerable amount 

 of time and trouble, but it costs at least L.E. 11 per 

 ton to import. We see therefore that cultivators are 

 really obtaining nitrate of soda at a cheap rate, in fact 

 much below commercial value. 



The one great drawback, however, is the fact that tafia 

 contains considerable and generally excessive quantities 

 of common salt and sulphate of soda. These salts are 

 often present in very large quantities. Continued use of 

 such material on any but basin lands would have a dete- 

 riorating effect on the soil, and for this reason it has been 

 objected to by some as a manure for cane. 



Summarising therefore, w r e may say that tafia is valuable 

 on account of the nitrate of soda it contains, the latter 

 varying from as little as \% to as much as 16%. Of 

 other valuable ingredients it contains but insignificant 

 quantities, that is to say of phosphoric acid and potash. 

 It contains however large quantities of salts. 



Analyses of 8 recent good samples made in the labor- 



