of certain Soils and Waters in Belgium. 41 



clone, and the quantity of sand determined by direct weighing, 

 the finely-divided earthy material was carefully dried at the 

 highest temperature it would bear without its organic consti- 

 tuents being injured, and then weighed. It was then carefully 

 but gently ignited in a current of air, until the organic mate- 

 rials were burned out, and was then again weighed. The loss 

 of weight gave the quantity of organic substance, together, 

 however, with some traces of water, from which the soil could 

 not be previously perfectly freed. 



The soil was then subjected, for the determination of its 

 chemical constituents, to precisely the same general plan of 

 treatment which I have described in the case of the ash. The 

 matter, insoluble in muriatic acid, was however found to be 

 (the sand and organic matters having been previously sepa- 

 rated) ferruginous clay, which it was not necessary further to 

 examine, as all the materials of importance, in studying the 

 chemical nature of the soil, had been taken up by the different 

 solvents used. 



In the case of the waters, the quantity employed for ana- 

 lysis was, with one exception, about two gallons ; in that case, 

 owing to a vessel having leaked (No. 3), but one gallon was 

 employed. The waters were, in the first instance, very care- 

 fully filtered ; and where any sensible quantity of sediment 

 was found upon the filter, its nature and quantity observed. 



The water was then evaporated, at first upon the sand-bath, 

 but finally upon a water-bath, to perfect dryness, and the re- 

 sidue having been collected and dried at 212°, was weighed. 

 It was then incinerated ; the residue, moistened with carbonate 

 of ammonia, again gently ignited and weighed. By the dif- 

 ference of weight, the quantity of organic matter present was 

 ascertained in the state in which it exists when dried at 212° 

 Fahrenheit. 



The solid material thus obtained was treated with water, 

 until all soluble salts were taken up, and the alkalies, lime, 

 magnesia, with sulphuric and muriatic acids, therein deter- 

 mined. The undissolved residue was next treated with muri- 

 atic acid, and the amount and nature of the earthy substances 

 taken up, as well as oxides of iron, &c., and phosphoric acid, 

 if any, ascertained. The material insoluble in muriatic acid, 

 when present, was of course determined. 



The detailed modes of analyses pursued in these cases were 

 precisely the same as in those of the ashes and soils. 



In carrying out the greater part of the practical details of 

 these analytical methods, I derived valuable aid from Mr. 

 William Sullivan, then my private assistant, but now first 

 chemical assistant in the Museum of Irish Industry, founded 

 by Her Majesty's Government in Dublin. 



