PHOSPHATES— SULPHUB. 659 



the soil containing the bone-dust, were as large as moderate-sized 

 goose-quills ; and the plants, in consequence of their having such strong 

 and Tigorous roots, grew to a size almost incredible. And not only were 

 they large, but they were strong and vigorous enough to support their 

 trusses without the aid of sticks, although many of the trusses con- 

 sisted of twelve, thirteen, and fourteen flowers each. The plants had 

 only a few sticks at the commencement of their growth, merely to keep 

 the branches at regular distances from each other. The flowers were 

 half as large again as usual. Some of these plants kept up a succession 

 of flower from four to six months. A few that were " spotted " were 

 put in soil containing the bone-dust, and in ten days they had put on 

 so many young leaves as to completely hide the "spotted" ones. This 

 dust was purchased cheap at a button factory in Bristol in 1839, but its 

 value being soon ascertained, in 1842 the price was more than doubled. 

 It is obvious that bone-ash only differs from button-dust in the want of 

 animal matter. 



The apparent effect of phosphates is to stimulate vegetation, 

 and to promote the formation of roots. It is in this way more 

 especially that they operate upon root crops, whose seeds form 

 their radicles rabidly under the influence of phosphoric acid, 

 and soon establish them securely in the ground beyond the 

 reach of dryness. All plants whose ashes have been examined 

 contain phosphates, which may therefore be regarded as universal 

 vegetable food. "Alkaline and earthy phosphates form in- 

 variable constituents of the seed of all kinds of Grasses, of 

 Beans, Peas, and Lentils." — Liebig. In Rhododendron ferru- 

 gineum they amount, according to Saussure, to 17'25 per cent. 

 To have any value it is, however, indispensable that they should 

 be soluble. Hence the insoluble phosphate of iron is useless 

 to vegetation. This is to be remembered in estimating the 

 worth of manure, for phosphates are now regarded as the most 

 important ingredient in manure, with the single exception of 

 ammoniacal salts. Hence when sewage water is deodorised by 

 salts of iron, the resulting phosphate being insoluble, the liquid 

 loses much of its value. 



Sulphwr. — " Plants contain, either deposited in their roots or 

 seeds or dissolved in their juices, variable quantities of com- 

 pounds containing sulphur. In these nitrogen is an invariable 

 constituent. Two of the compounds contaiaing sulphur exist 

 in the seeds of cereal plants, and in those of leguminous 



