164 REPORT OF THE 



The following analysis is said to have been made by Dr. S. 

 P. Duffield, of Detroit: 



* Grand Rapids. Ohio. 



Water 19.00 20.10 



Lime 32.67 32.21 



Sulphuric acid 44.44 45.95 



Organic matter and loss, 3.89 1 . 08 



100.00 100.00 



Here, on the contrary, the Ohio gypsum contains the most 

 sulphuric acid. It appears, however, that the quantity stated 

 for the Grand Rapids sample, is not sufficient to neutralize the 

 lime by 2 . 23. 



By unfair selection of samples, such analyses may be made 

 to show anything. The gypsum as it finds its way to the mar- 

 ket is a mixture of different grades. The only true test would 

 be an analysis of average samples taken direct from the mar- 

 ket, not picked for the occasion. The samples sent Prof. Pisk 

 were nearly the best of each. It is but justice to say, how- 

 ever, that a large proportion of the Giand Eapids gypsum, is 

 equally fine with the specimen analyzed. 



I have been unable to ascertain the extent of the plaster 

 business at Grand Rapids during the past year. While this 

 report is passing through the press, I am furnished by Mr. 

 Freeman Godfrey with some interesting facts relative to the 

 operations of a new company, and I desire to stimulate other 

 companies to a greater attention to their true interests, by 

 making the following brief mention of the " Florence Plaster 

 Mills," near Grand Rapids. 



Last October Mr. Godfrey purchased 103 acres of land upon 

 Plaster Creek, upon the south side of Grand River, and at once 

 began extensive preparations for the quarrying and grinding of 

 gypsum. At present the mill which has been erected is turning 

 out 40 tons of ground plaster per day, and Mr. Godfrey intends 

 putting in another run of stone next summer, and erecting a 

 building for the manufacture of stucco. The quarry is situated 

 in close proximity to the mill. The plaster is reached by strip- 



