SALTS. 



SALTS. 



Wood of hazel, May 1 .... 94-5 



Bark of do. - - - - .- - 125 



Wood of mulberry, November - - 21- 



Wood of hornbeam, November 22- 

 Wood of horse-chestnut, May 10 - - 95 



Fruit of do., October 5 - - - - 82- 



Plants of peas (Pisum satirum) in flower 49'8 



Do. ripe 34 25 



Plants of vetches (View, faba.) before 



flowering, May 23 - 55'5 



Do. in flower ..... 55'5 



Do. ripe, July 23 50- 



Reeds of do. 6928 



Do. in flower raised in distilled water - 60*1 



Plants of tamsole, June 23 o3- 



Wheat, in flower ----- 43'25 



Do., seeds ripe ----- 11- 



Do. a month before flowering 60' 



Do. in flower, June 14 - - - - 41- 



Do., seeds ripe 10- 



Bran 4416 



Plants of maize or Indian corn - - 69- 



Ohaff of barley 20- 



8*edsofdo. 29- 



Oats - 1- 



Leaves of fir (Pinua abics), raised on 



limestone ------ 16* 



Leaves of fir, raised on granite - - 15* 



Branches of pine .... - 13- 



M. Vauquelin found 20 per cent, of potash 

 in the ashes of the oat ; and from his experi- 

 ments it is probable that potash exists in plants 

 in combination with the acetic and carbonic 

 acids. 



The mineral alkali soda, or carbonate of 

 soda, is found in almost all the plants which 

 are found growing in the sea, or on the shore, 

 within reach of its influence. The amount of 

 alkali which these produce, is considerably 

 greater, in proportion to that produced by 

 plants natives of inland places. Thus, 100 

 parts of the salsola soda yield 19-921 parts of 

 ashes, and these contain 1-992 parts of soda 

 and common salt. Many plants, the vegetable 

 marrow and the vine, for instance, derive great 

 benefit from the application of soda to their 

 roots. Soap-suds are used as an excellent 

 liquid manure by many gardeners. 



Sea-weed, kelp-soda, barilla, and the com- 

 mon washing-soda of the shops, have all been 

 used successfully as saline manures ; and the 

 well-known fertilizing mixture of salt and lime, 

 after it has remained undisturbed for some 

 time, contains chloride of lime and soda in 

 abundance. Sea-weed abounds with a strange 

 mixture of alkaline salts, and there is no green 

 manure more powerful in its effects than this, 

 especially when it is ploughed in as fresh as 

 possible. Mr. Gaultier de Claubry found in the 

 Fucus saccharinus and in the Fucus digitatus 

 (which is much used in Scotland as a manure) 

 the following substances saccharine matter, 

 mucilage, vegetable albumen, oxalate of pot- 

 ash, malate of potash, sulphate of potash, sul- 

 phate of soda, sulphate of magnesia, muriate 

 of soda, muriate of potash, muriate of magne- 

 sia, carbonate of potash, carbonate of soda, hy- 

 driodate of potash, silica, phosphate of lime, 

 phosphate of magnesia, oxide of iron, oxalate 

 of lime. In the islands of Guernsey and Jer- 

 sey they employ the ashes of the sea-weeds, 

 which they call vraic. Half a bushel strewed 

 over a perch of ground in winter, or the be- 

 ginning of spring, is sufficient. It gives a full 

 ear to the corn, and prevents it from being laid. 



"Phosphate of lime, which is composed, ac- 

 cording to the experiments of M. Berzelius, of 



phosphoric acid 100 parts, and lime 84-53, 

 abounds in vegetable substances. It forms the 

 basis of bones, from which, for the purposes 

 of experiment, it is commonly procured. Ob- 

 tained in this way it is always in the form of a 

 white powder, without either taste or smell ; is 

 insoluble in water, and unaltered by exposure 

 to the atmosphere. Phosphate of magnesia is 

 composed of phosphoric acid and magnesia ; 

 is a salt soluble in 15 times its weight of water. 

 These two salts have been found in a variety 

 of vegetable substances by MM. Vauquelin, 

 Saussure, and other able chemists. See BONES. 



There is little doubt but that these salts are 

 absorbed from the soil by the plants. Almost 

 all cultivated soils contain them in some form 

 or other; and of the value of their addition to 

 the soil in almost every form, there is consi- 

 derable evidence. Thus, phosphate of lime 

 abounds in all the richest animal manures, 

 such as in bone-dust and the richest excre- 

 ments of animals; and, again, it is found by 

 the Cheshire graziers, that the earthy salts of 

 bones obtained from the size-makers, after 

 most of the oily matters are removed by the 

 action of steam, and hardly any thing but the 

 salts of lime remain, are quite as fertilizing to 

 their pastures as when used in their fresh 

 state, abounding with animal matters. 



Sulphate of Hme, or gypsum, is another salt, 

 which is invariably found in and promotes the 

 growth of certain plants. 



It must, I think, be regarded as one of those 

 salts which constitute the food or constituents 

 of plants. It is always present in the clover, 

 lucern, and sainfoin, and in smaller propor- 

 tions in the potato and the turnip. See PLAS- 

 TER OF PARIS. 



That it is a food for plants, was the opinion 

 of Sir Humphry Davy. He remarked, when 

 speaking of gypsum and the alkalies, "It has 

 been generally supposed that these materials 

 act in the vegetable economy in the same man- 

 ner as condiments or stimulants in the animal 

 economy; and that they render the common 

 food more nutritive. It seems, however, a 

 much more probable idea, that they are ac- 

 tually a part of the true food of plants, and that 

 they supply that kind of matter to the vegeta- 

 ble fibre, which is analogous to the bony mat- 

 ter in animal structures. Thus, those plants 

 which are most benefited by the application 

 of gypsum, are those which always afford it 

 on analysis. Clover and most of the artificial 

 grasses contain it, but it exists in very mi- 

 nute quantity only in barley, wheat, and tur- 

 nips." (Jig, Chem. p. 19.) And it is notice- 

 able, that most of these remarks apply to the 

 phosphate of lime (which can hardly be re- 

 garded as a stimulant), since it is not even 

 soluble in water ; it is also worthy of observa- 

 i tion, that the same salts of lime (the phosphate 

 ' and the carbonate) which Davy thus supposes 

 to be placed in plants to add to their strength 

 and solidity, are precisely those salts which for 

 that very purpose are placed in the bones of ani- 

 mals. They thus, as it were, mutually nourish, 

 each other. The very phosphate of lime, which 

 in the dissolving bone-dust is absorbed by the 

 plant, again becomes, in the food of animals, a 

 material for the formation of other bones. 



975 



