*0 CHEMISTRY AND USES OF THE POTATOE. 



the sweet potatoe, the only root known before this period)* 

 being likewise a food as also a meat for pleasure, equal in 

 goodness and wholesomeness unto the same being either 

 roasted in the embers or boyled and eaten with oyle, vine- 

 gar, and pepper, and dressed in any other ways by the 

 hand of one cunning in cookeries;" so that at first it was 

 used as a luxury, and not as an article of food. 



(70.) Evelyn states, " the root being roasted under the 

 embers or otherwise roasted, with a knife the pulp is but- 

 tered, in the skin of which it will take up a good quantity, 

 and is seasoned with a little salt and pepper. It is also 

 stewed and cooked in pyes." 



(71.) The potatoe is valuable to man as an article of 

 food, from the starch and albumen which it contains, as 

 these two principles can effectually nourish the human be- 

 ing. The one acts by combining with oxygen in his lungs 

 to give him warmth ; the other nourishes his muscular 

 system and fits him for labor. 



(72.) Neither principle alone would suffice, for man 

 would starve upon either one ; it is the combination then 

 which is valuable, and we find that this combination cannot 

 be produced at so cheap a rate from any other source. 



(73.) The nitrogenized portion is the most costly to buy, 

 and we find that the relative value of the potatoe, in point 

 of weight with other substances, is as follows : 



Maize, or Indian corn . 138 



Wheat flour .' . * . 100 



Barley . . . . 130 



Oats U- . . - . 117 



Rye .... Ill 



Rice . . . .177 



Buck wheat ... 108 



Peas .... 67 



Potatoes . . . .613 



dried at 212 C . 126 



Jerusalem artichokes . 539 



Turnips . . . 1338 



These are termed nutritive equivalents, 613 parts of 

 potatoe being equal to 100 wheat flour, &c. 



