17 



POTASH COMPOUNDS. 



Thirty-two samples have been inspected, represent- 

 High Grade ing sixteen analyses. There was only one case where 

 Sulfate of the potash guarantee was not maintained. The 



Potash. average retail cash price for this salt has been $49.85, 



and the average calculated commercial valuation $52.19 per ton. 

 The average analysis of high grade sulfate of potash showed 49.70 

 per cent of potassium oxide. The pound of actual potash in this 

 form has cost, on the average, 5.02 cents. Only one sample showed a 

 commercial shortage of over 50 cents per ton. 



Lozv ell Fertilizer Co., No. 216 Potash found 47.48%, guaranteed 48%. 



Six analyses have been made, and the potash guarantee 

 Potash- was maintained in all but one case. The average retail 



Magnesia cash price has been $29.60 and the average calculated 

 Sulfate. commercial valuation $28.79 per ton. This salt has 



tested on the average 27.42% actual potash. The aver- 

 age cost of a pound of potash from this source has been 5.40 cents. 

 Three samples have shown an abnormally high percentage of matter 

 insoluble in water. This has been explained as follows by Dr. 

 Huston of the German Kali Works, to whom the matter was referred 

 by the fertilizer companies involved: 



"The older grades of sulfate of potash-magnesia contained an 

 excess of magnesia; while under the present working methods the 

 mills have difficulty in supplying materials with a minimum of 25 per 

 cent of sulfate of magnesia or 8.33 per cent actual magnesia. The 

 sulfate of potash-magnesia formerly on the market used to contain 

 about 11 per cent of magnesia, but the methods of manufacture have 

 changed so that only about 20 per cent of sulfate of magnesia has been 

 found in the product." Dr. Huston further states that "last March 

 a commission was appointed in Germany to take up the composition 

 of sulfate of potash-magnesia, and it was finally decided to have the 

 standard material in the future contain 25 per cent sulfate of mag- 

 nesia or 8.33 per cent actual magnesia (MgO)." It is Dr Huston's 

 opinion that the samples containing the low magnesia tests were 

 shipped previous to the proposals made by the German Commission 

 and during a period when no attempt was made to control the amount 

 of magnesia in the material. In conversation with the writer. Dr. 

 Huston explains the presence of the insoluble matter in the samples by 

 saying that some of the refuse salts used in making the sulfate of 

 potash-magnesia naturally contained a relatively high percentage 

 of siliceous material. 



From the above it would seem that salt formerly known as sul- 

 fate of potash-magnesia is a thing of the past, and that the product 

 known by that name in the future will in reality be a "dry mix" 

 composed of sulfate of potash and refuse magnesia salts; the final 



