MARROW. 255 



softens by the heat of the hand, and melts when heated to 113. 

 When cooled slowly, it crystallizes in sphericles like olive oil. 

 It burns with a flame like tallow. When distilled, it gives first 

 a transparent fluid yellowish oil, accompanied by carbonic acid 

 gas, water, and heavy inflammable air. Afterwards there comes 

 over a white solid oil, accompanied by a less copious evolution of 

 gaseous bodies, and which does not become dark-coloured, as 

 happens when tallow is distilled. This had already been observ- 

 ed by Neumann. This solid oil has a disagreeable smell, amounts 

 to 0-3 of the marrow distilled, reddens vegetable blues, and when 

 boiled in water, gives out a portion of sebacic acid, which Berze- 

 lius considered as benzoic acid. 



The empyreumatic oil combines readily with alkalies and their 

 carbonates. With the latter it forms a snow-white soap, insolu- 

 ble in water, though it increases in bulk when placed in contact 

 with that liquid. It combines also with the earths, and forms 

 soaps likewise insoluble in water. 



The water which comes over during the distillation of marrow 

 is colourless, has a fetid and sour smell, and an empyreumatic 

 taste. It contains a little acetic acid, empyreumatic oil, and pro- 

 bably sebacic acid ; but exhibits no traces of ammonia. 



The gaseous products amount to -^th of the marrow distilled. 

 They contain no sulphur nor phosphorus, and consjst of carbo- 

 nic acid and heavy inflammable air, which burns with a white 

 flame, and seems to contain oil in solution. 



The charry matter in the retort amounts to 0-05 of the mar- 

 row distilled. It is dark-brown, heavy, and brilliant It is inci- 

 nerated with difficulty, and leaves an ash consisting of phosphate 

 of lime, carbonate of lime, and some soda. 



5. Concentrated sulphuric acid dissolves marrow without the 

 assistance of heat. The solution has the appearance of a brown 

 syrup ; and when the acid is diluted with water, the marrow se- 

 parates unaltered. When heat is applied, the acid decomposes 

 the marrow and forms a resinous coal. 



Diluted nitric acid digested on marrow, in a moderate heat, 

 renders it yellow, and gives it more consistence, and the smell of 

 old bones. Concentrated nitric acid dissolves marrow without 

 the assistance of heat, and the marrow is not precipitated by the 

 addition of water. 



6. Marrow combines with alkalies and forms soap. Boiling 



