22 



JOURNAL OF THE 



Fine ground Charleston Rock, - - - 1,100 pounds. 

 Sulphuric Acid, 470 B - - - - - 950 



Several tons of it we. e made November 21st, 1883, and a sample 

 of it was drawn by myself November 22d. The sample was pulver- 

 ized by hand as fine as possible, and analyzed at once. 



Fifty grains of the sample were then taken and dried at a temper- 

 ature of 90=^-100° C. for two days. At the end of that time a sample 

 was drawn, pulverized until it passed through a sieve of 100 meshes 

 per square inch, and analyzed. 



The drying was continued for eight (8) days longer, at the end of 

 which time a sample was drawn, passed through a 100 mesh sieve, 

 and analyzed. 



Tabulating these results for convenience of reference we have : 



We have here a loss of 4.26 per cent, of Sol. Phos. acid in days, 

 a loss of .47 per cent of Insol. Phos. acid, and a gain of 4.74 per 

 cent, of Reverted. Ordinarily the loss of Soluble is compensated 

 by the gain of Reverted, while the Insoluble remains about the 

 same. Post, in the article before referred to, claims to have found 

 that in the course of six (6) months, in sealed bottles, some of the 

 Soluble becomes so Insoluble as not to be dissolved by Am. Citrate 

 at 90° C. But here it is shown that in ten (10) days at a temperature 

 of 90 — 100° C. Some of the originally Insoluble Phos. acid, viz: 

 .47 per cent, aas 6ecome Soluble in Am. Citrate at 40° C, that is, 

 has changed to Reverted ! But this loss of .47 percent, of Insol. 

 Phos. acid is doubtless due to the very fine grinding of the dry 

 samples. For the difference in Insol. Phos. acid between the fir-t 

 and second analyses is .37 pei cent., while the differeiice between 

 the second and third is only .10 per cent. That is to say, the differ- 

 ence between the Insol. Phos. acid in the sample pulverized by 

 hand, and the sample dried for two (2) days and then passed through 

 a 100 mesh sieve is .37 per cent, in favor of the finely pulverized. 



