82 



On the Inorganic Constituents of Plants, 



darker foliage. About five weeks after applying the salts, the 

 standard square and that treated with Sulphate of Lime, were the 

 poorest, those which had Muriate of Potash and Phosphate of 

 Lime, were rather finer ; those manured with Sulphates of Soda, 

 Magnesia, and Potash, still better ; that which had been manured 

 with common Salt, resembled in size and appearance those which 

 had been treated with the sulphate, but the foliage was remarkably 

 pale in colour ; whilst those manured with Ammoniacal Salts and 

 Nitrate of Soda, were distinguished from all the others, by the 

 plants being several inches higher, having much thicker stems, and 

 a rich dark green foliage. One of the rows in the bed manured 

 with Muriate of Ammonia had from some cause failed, at least the 

 plants had not come up at the time of applying the manures, 

 within a very short time afterwards, however, they came up, and 

 grew with such vigour and luxuriance that in a few weeks it was 

 impossible to distinguish them from the other plants similarly 

 manured. The plants continued to grow until the end of August, 

 and the same general distinctions already mentioned, were evident 

 to the last. The ammoniacal manures and the Nitrate of Soda 

 produced the finest plants, but the differences between the squares 

 though evident, were far less marked at the end of August, than 

 they had been at the end of June, and through the whole of July. 

 It appeared as if the four manures just referred to, produced a 

 powerful effect on the plants for the first six weeks, and caused 

 them to grow with great vigour, so that they soon came to their 

 full size, after which they ceased to grow ; whilst the plants in the 

 other squares never made any rapid growth, but continued to grow 

 slowly and steadily until the tops began to die off. In the middle 

 of September, as the greater part of the tops were either dead or 

 dying, they were gathered, and the potatoes taken up. The different 

 manures were all applied at the rate of three hundred weight per 

 acre, excepting the Phosphate and Sulphate of Lime, both of which 

 were used at the rate of four and a half hundredweight per acre. 



