CHEMISTRY OF THE POTATO. 



67 



three-fourths of their entire weight. In the stems a like 

 variation in the proportion contained is seen ; the average 

 amount may be taken at 86 to 88 per cent. The percen- 

 tage of ash or inorganic matter in the tubers varies from 

 '75 to 1-58; the mean of many determinations by From- 

 berg is '87 per cent. In the tops or "shaws" the per- 

 centage averages about 2 per cent. The composition of 

 this inorganic matter or ash is given as follows: 



Some more recent analyses of the inorganic matter of 

 the potato tuber have been published, and are given in 

 the table below. These differ from the foregoing princi- 

 pally in the absence of the silica and the chlorine, which 



1 Johnston, the mean of several. 2 Fromberg, do. 8 Thomas, do. 



* Varieties analyzed:!. White Apple; 2. Prince's Beauty; 3. Ax bridge 

 Kidney; 4. Magpie; 5. Forty-fold. 



