SOME PKAS REFUSE TO BOIL SOFT. 519 



Independently of all api)lications to the soil, I believe it is generally 

 observed that good boilers are produced ujjon light, sandy, and gravelly 

 soils ; while heavy, wet, undrained (and newly broken up ?) land usually 

 produces bad boiling peas and beans. Thus melting peas {sidder peas, 

 as they are locally called) for the Birmingham market are grown on the 

 slopes of the gravelly hill of Hopwas, two miles from Tamworth, on 

 ihe Lichfield road — the red clay lands of the vale of the Tame produc- 

 ing in general pig* peas or beans only. It is on similar soils that melt- 

 ing barley and mealy potatoes are produced, and the effect upon the 

 three crops may probably be due to a common cause. 



At all events it is probable — 



a. That the boiling quality of the pea crop is not owing to the qual- 

 ity of the seed — since peas of both varieties have been raised from the 

 same seed.f 



b. That it is not generally owing to the seasons, since some land pro- 

 duces hard peas every year. If the wetness of the soil indeed have any 

 influence, a rainy season may cause the production of bad boilers upon 

 land from which soft peas are usually reaped. 



4°. Chemical difference between the two varieties of pea. — Why does 

 one of these varieties of pea melt more readily than the other ? For 

 the same reason very nearly that one potatoe boils mealy, and another 

 waxy, and that one sample of barley melts better in the mash-tub than 

 another. Melting peas and barley and mealy potatoes contain a larger 

 proportion of starch tlian samples which are possessed of an opposite 

 quality. 



The pea, as we have seen, consists essentially of legumin and starch. 

 The former coagulates and contracts, or runs together into a mass by 

 boiling, — the latter, on the contrary, expands,* becomes more bulky, tends 

 to burst the husk, and to separate into single grains. If the tendency to 

 contract and cohere be greater than the disposition to expand and sepa- 

 rate — in other words, if the legumin predominate — the pea does not melt, 

 while if the starch be abundant the pea boils well. It is possible that 

 the addition of a little soda may cause hard peas to melt, since legumin 

 is soluble in a solution of soda, but in waters impregnated with lime all 

 peas are said to boil soft much less readily than in such as are free from 

 that ingredient. [Dumas, Traite de Chimie, vi.] 



It is only when peas and beans are raised for the food of man that the 

 possession of the melting property becomes a matter of importance. It 

 is rather because they are more agreeable to the palate than because they 

 are ascertained to be more nutritive, that they are preferred in this state. 

 When wo come to consider the feeding of stock, we shall see that, ac- 

 cording to the present state of our knowledge, the opinion may rea- 

 sonably be entertained that insoluble peas are really better adapted for the 

 feeding and fattening pigs and other stock — the purpose for which they 

 are employed — than those which are possessed of the melting quality. 



It is a difference in the chemical composition of the seeds of legumi- 

 nous plants that makes them melt more or less easily — but by what 



* Much used for the feeding of pigs. 



t Some however suppose it to depend upon the age of the seed, or the time of aowing. 

 •^British Husbandry, ii., p. 217. 



