OF THE POTATOE. 435 
the ashes of wheat and potatoes, is, according to 
Boussingault, in 100 parts. 
Wheat Potatoes. 
Phosphoric Acid..........2+6+ 47.0 i UWS: 
SUIpMUTIC GIG \<.sc.c.0:-200s 1.0 Gal 
Carbonie “Acid........02..ccce0- 13.4 
Chioritient.2 200 6.3 Las. traces 2.7 
Mat Oy 2442 2 Ss god deascp ch .tosidon 2.9 1.8 
ACER inane ncnnnschnss 15.9 5.4 
OG ee ans accession cote wees ou 29.5 Fas 
DOU B cciscs vv cceetececsssue tess traces traces 
S11 rd See Apap antes tbs 1.3 5.6 
Alumina, (e206... 22. SI 0.5 
Moisture and loss ............ 2.4 9.0 
The silica in wheat-straw amounts to 67.6 
per cent. 
I shall now make some remarks upon that 
portion of M. Payen’s table, which has reference 
to the productiveness of the potatoe. 
It is stated, that 1 cwt. of seed of the Rohan 
variety produced 58 cwt., and that the others 
varied to 32 ewt., according to the quality planted. 
It would therefore, only require 5 ewt. or 560 lbs. 
of seed per acre, in every instance, to produce 
the crops mentioned in the table. 
