SALTS. 



SALTS. 



The carbonate of lime, in some of its forms 

 of chalk, limestone, marl, &c., is the most uni- 

 versally present of all the salts contained in 

 vegetables. It is, in minute proportions, solu- 

 ble in water, and more so if the water is satu- 

 rated with carbonic acid gas, hence it is readily 

 absorbed by the roots of plants. It exists in 

 vegetables in very varying proportions; thus, 

 the ashes of the perfect oat plant, straw and 

 seed together, were proved by M. Vauquelin to 

 contain more than 5 per cent, of this earth. 

 (Ann. de Chem. vol. xxix. p. 19.) In 32 ounces 

 of seeds of wheat, M. Schraedar found 12 

 grains of carbonate of lime; and in the same 

 quantity of seeds of rye 1 3-4 grains ; 24-8 grains 

 in seeds of barley; 33-75 in those of the oat; 

 and 46-2 in the same weight of the straw of 

 rye. It is most commonly, although not al- 

 ways, found in vegetables with carbonate of 

 magnesia. These were found together by M. 

 Saussure in the ashes of the following different 

 substances. He obtained from 100 parts of 

 the ashes of the 



Part*. 



Leaves of oak, gathered in May - - - 12 



Do., September ----- 23- 



Bark of the oak 63-25 



Wood of oak 23- 



Soil from wood of oak - - - - 10- 



Wood of poplar ----- 27- 



Wood of hazel .... - 8- 



Wood of mulberry ----- 56- 



Wood of hornbeam ----- 26- 



Plants of peas, in flower 6- 



Do. of vetches, in flower" - 4-12 



Do. raised in distilled water - - 0- 



Wheat in flower 0-25 



Do. seeds, ripe - - - - - 0'25 



Do. straw ------ ! 



Do. bran ------ 0' 



Oat seeds 0- 



Barley seeds ------ 0- 



Do. chaff ------ 12-5 



Leaves of Rhododendron ferruffineum, 



raised on limestone - 43-25 



Do. raised on granite - 16-75 



Leaves' of fir, raised on limestone - - 43-5 



Do., raised on granite - - - - 29' 



Now, these two soils (the granite and the 

 limestone) contained carbonate of lime in the 

 following proportion : 



Granite. Limestone. 



Carbonate of lime - - - 1'74 98- 



Alumina 1325 0-625 



Silica 75-25 



Petroleum ----- 025 



Iron and manganese - 9- 0-25 



IJim 99-275 



Carbonate of lime has also been detected in 

 the sap and white matter of the ulcer of the 

 elm by M. Vauquelin; in the ashes of worm- 

 wood (more than 50 parts in 100), by Kuns- 

 muller; in the flowers of the arnica, by M. 

 Chevalier ; in the potato, by M. Einhof ; in the 

 red bark of St. Domingo, in Peruvian bark, and 

 in the wood of the quingania, by M. Fourcroy. 

 Existing, therefore, so universally in plants, 

 there can be no doubt of the fact that this salt 

 is fulfilling, then, some wise and salutary pur- 

 pose ; not fortuitously, but with design ; not by 

 chance, but by the regulation and arrangement 

 of their Divine Architect. 



The action of saltpetre or nitrate of potash 

 upon vegetation is not so easily explicable as 

 that of many other salts ; and the same remark 

 applies to that of cubic petre or nitrate of soda. 



Nitrate of potash, which is composed of ni- 

 976 



trie acid 54-34 parts, and potash 45-66 parts, 

 enters into the composition of a few plants, it 

 is true, but in the greater number, even in 

 those of the farmer's crops, on which on some 

 soils its application produces such luxuriant 

 effects, its presence cannot be detected, even 

 in minute proportions. Some plants, however, 

 do contain it in considerable quantities. Thus 

 it has been found in the common nettle, the 

 horse-radish, and the sunflower. M. Chevalier 

 found it in the Chcnopodium olidum ; M. Vau- 

 quelin in the leaves of the deadly nightshade; 

 M. Chevreul in woad ; Dr. John in the Mesem- 

 bryanthcmum crystallinum. M. Boullion Le- 

 grange made various plants, such as the sun- 

 flower, vegetate in soils which did not contain 

 any saltpetre: upon examining them, no traces 

 of saltpetre were discernible, but upon water- 

 ing them with a weak solution, it made its ap- 

 pearance in them as usual. (See NITRATES.) 

 The presence of cubic petre (nitrate of soda), 

 which is composed of nitric acid 62-1, and soda 

 37-9, is still more rare in plants ; it has only 

 been detected in barley. 



The salts formed with the vegetable acids 

 existing in the juices of plants are rather nu- 

 merous. Oxalate of potash, for instance, exists 

 in the Oxalis acetocella, and several others ; 

 oxalate of lime in rhubarb, parsley, fennel, 

 squills, tormentilla, deadly nightshade, and spi- 

 nach. Nitrate of lime is contained in the onion; 

 malate of lime in the houseleek, wake-robin, 

 mignionette ; and malate of potash in rue, the 

 garden purslane, nasturtians, lilac, madder, &c. 



There is, perhaps, no saline substance that 

 exists to so great an extent in marine plants, 

 and which has been used for so long a period 

 and to such an extent for those growing in in- 

 land situations, as common salt. (See SALT.) A 

 substance which not only abounds in all plants 

 growing on the sea-shore, but always exists in 

 smaller proportions in many of those growing in 

 upland districts. Thus, Mr. G. Sinclair obtained 

 from 1450 grains of wheat-chaff from Bedford- 

 shire, ashes 50 ; common salt 2 J : from 1450 parts 

 of the seed, ashes 10 ; common salt . But from 

 the same crop, which had been dressed with 44 

 bushels of common salt per acre, he obtained 

 from 1450 parts of the chaff, ashes 40 ; com- 

 mon salt 4 : and from 1450 parts of the seed, 

 ashes 10; common salt |. 



Common salt is found generally in minute 

 proportions in most cultivated soils. Davy 

 detected in 400 grains of a good silicious soil 

 from a Tonbridge hop-garden, nearly 8 parts 

 of common salt. 



Besides being in small proportions a direct 

 food for plants, common salt also seems to 

 perform several other services to vegetation, 

 and the same remark probably applies to other 

 salts ; for instance, when applied to the soil in 

 small proportions, it certainly promotes the 

 putrefaction of its organic matters. See SALT. 



And again, salt, in common with several 

 others, appears to excite or stimulate the plant, 

 when applied to it in proportions not too ex- 

 cessive ; a fact first noticed by Dr. Priestley. 



Another use of common and other salts to 

 vegetation is, the preservation of the plant 

 from injury by sudden transitions in the tem- 

 perature of the atmosphere : salted soils only 



