BY THOS. STEEL. 215 



This pieparation, after drying at 150° C, calculated free troui mineral 

 matter, gave the results below, on ultimate analysis. Humus is known to have 

 a somewhat variable composition ac-eoi'ding to source and method of prepara- 

 tion. When made from sugar, for instance, it may be quite Free from nitrogen. 

 For comparison 1 have inserted analyses of humus from a number of sources, 

 references to which are given. 



Aiiali/ses of Humus Derived from Various Sources. 



1. 2. 3. 4. 



Carbon 50.53 57.75 53.42 52.71 



Hydrogen 5.G7 5.43 5.16 3.08 



Oxygen 43.20 36.02 40.92 41.49 



Nitrogen (50 .80 .50 1 .82 



100.00 100.00 100.00 100.00 



1. Black sandstone. New South Wales. 



2. Brown Peat. Watt's Diet. Cliem., vol. viii., 1870. p. (ilO. 



3. Decaved Fir wood. i .. ,,, „ ,„,,,. ., .. „„„ 

 . ^ * , ^ , 1 Jour. ehem. Soc. 1900, Abs. n., p. 388. 



4. Decayed Oak woo<l. ) 



A preparation of humus made by treating black soil from Blackheath, N.S. 

 Wales, with pota.sli, and precipitation with sulphuric acid, behaved in all re- 

 spects in a numner identical with the black sandstone preparation. 



I would propose the name Ulmite for this form of hunuis as found coating 

 sandstone grains. 



Samples of black sandstone were supplied to me by Mr. W. S. Dun, of tlie De- 

 partment of Mines, from McAuley's lead, Esk River; Iluka, t'larence River; and 

 Sans Souci, near Sydney. They were in all respects similar to ray specimen 

 from Tweed Heads. 



A similar coating to the above occurs on the rounded grains and pebbles of 

 rock phosphate whii'h constitute the surface "soil," four to six inches in depth, 

 on Ocean Island (Jour. Soc. Chem. Tud,, xl., 1921, p. 59t). 



