3G8 Dr Daubeny's Speculations as to the 



and carbon, may in great measure supersede the want of animal manure ; 

 and if the rock happens also to contain a portion of the earth}- phosphates, 

 there is no reason why the celebrated Terra del Lavoro should not con- 

 tinue to produce an unintermitted succession of corn crops, repeated as 

 often as the disintegration of the substratum permits, so long as the vol- 

 canic processes seated underneath it continue to send forth volumes of 

 the gases alluded to. The superior quality of the wheat grown in this 

 part of Campania may perhaps be thought to confirm such a conjecture. 

 It would appear, that the flour of warm climates in general contains more 

 gluten than that of colder ones,* perhaps because heat promotes the 

 decomposition of organic matters, and consequently renders the supply 

 of ammonia more abundant ; and to this circumstance its superior fitness 

 for the manufacture of macaroni is generally attributed. But the Nea- 

 politan macaroni is distinguished for its excellence, and hence it is pro- 

 bable, that the wheat grown in the neighbourhood of that city, which 

 supplies the raw material for this article of food, will be found to con- 

 tain a larger pcr-centage of gluten than common, the power of forming 

 which might be communicated to it by the ammoniacal salts in which its 

 soil so abounds. 



* See Davy's Agricultural Chemistry, p. 141, and Mr Hyett's interesting com- 

 munication in the Eng. Agric. Journ. No. 5, for January 1841. 

 Boussingault, Ami. Chimie, p. G5 — 301, says that — 



Violet-hearded wheat, from Alsace, contains . 17.3 per cent. 



The same, grown in the Jardin des Plautcs, . 23.7 — 



Winter wheat, grown in ditto, . . . 33.3 — 



Hermbstoedt has given the following results, Annalen der Landwerthschaft, 

 vol. xxii. p. 1. 



100 parts of wheat in soil manured w 



Human urine (dried), 

 Bullock's blood (dried), 

 Human feces (dried), 

 Sheep's dung, 

 Pigeon's dung,f 

 Cow's dung, 

 Vegetable humus, 

 Same soil not manured, 

 Sir H. Davy found — 



lOOpts. good full grained wheat, sown in autumn 



to afford ..... 



100 pts. of wheat sown in spring, 

 100 pts. of Sicilian wheat, . 

 100 pts. of Barbary wheat, . 

 100 pts. of full and fair Norfolk barley, 

 100 pts. of Suffolk rye, 



1 It seems extraordinary that pigeon's dung should stand lower in the scale than that of 

 sheep. 



