170 CALCAREOUS MANURES— APPENDIX. 



from which some geine is separated when it is again acted on by water. 

 If this solution is left to evaporate spontaneously in contact with air, it 

 becomes covered with an insoluble pellicle, and when a certain degree of 

 concentration has been reached, the liquor becomes turbid. The solution 

 is precipitated by the salts of tin and of lead; after the precipitation, the 

 liquor is without color. According to Korte, the sulphuretted hydrogen 

 gas precipitates it also. This extractive matter is contained in the water 

 of many springs and streams. The water of the springs of Porla, in West- 

 rogotha, contains so great a quantity that it is colored yellow. When the 

 iron contained in this water is oxidized from the air, the extract of mould 

 is precipitated with the oxide of iron, and the water becomes clear. 



Geine. — This substance has received different names. Braconnot has 

 given to it the name of ulmin, for reasons which I have exhibited and op- 

 posed in a former part of this work. Dobereiner and Spi'engel gave to it 

 the name of acid of humus, because it combines with the earths and alka- 

 lies. But for the same reason we might give the name of acid to more 

 than the half of all vegetable bodies. 



Geine does not exist in vegetable earth only ; soot contains it also, and 

 according to Braconnot, it is formed when the saw-dust of wood is ex- 

 posed to the action of caustic potash. It is almost impossible to obtain 

 geine in a state of purity. One part of geine which is met with in a natu- 

 ral state is in combination with bases ; but when we attempt to remove 

 these by an acid, the geine combines in part with the excess of acid, and 

 acquires itself (in part) the property of reddening vegetable blues. Geine 

 possesses all the properties of apotheme, and it is produced like other apo- 

 themes; that is to say, by the action of the air on dissolved extract of 

 mould. In the natural state it does not act chemically, either like the acids 

 or the alkalies. Nor does it have any effect on the color of vegetable blues. 

 It is but slightly soluble in water, which it colors of a pale yellow; is still 

 less soluble in alcohol, and insoluble in ether. Exposed to the action of heat 

 it takes fire, burns at first with flame, then without ilame like spunk, spread- 

 ing a peculiar odor, something like that of burning peat. Submitted to dry 

 distillation, it is decomposed, gives half its weight of a charcoal having 

 a metallic lustre, of empyreumatic oil, an acid water containing acetic acid 

 and sometimes ammonia, some carburetted hydrogen, and a little carbonic 

 acid gas. If geine is held suspended in water, through which a current of 

 chlorine is passed, this whitens it, and precipitates a white resin-like sub- 

 stance. Iodine is without action on it. If we add an acid to an alka- 

 line solution of geine, the geine is precipitated. If the whole of the geine 

 is not precipitated, that part which is precipitated retains in combination a 

 small portion of the base, and leaves, when it is burnt, a small quantity of 

 alkaline ashes. If, on the contrary, an excess of acid is poured into the al- 

 kaline solution, the liquor is discolored, and the precipitated geine strongly 

 reddens vegetable blues, a property which cannot be removed by placing 

 the geine on a filter, and pouring water upon it. So long as the liquor 

 which passes through the filter contains free acid it is not colored ; then it 

 begins to be colored, and finally it dissolves as much as two-thirds of its 

 weight of the precipitated mass. These acid properties belong in part to 

 the geine, which owes them to the action of the alkali, and which may, in 

 this case, be called geic acid; they ought to be in part attributed to a com- 

 bination of the geine with the precipitated acid. According to EinhofF, it 

 is the latter case which is really presented, and the acid cannot be carried 

 off, but with the aid of an alkali. SprengeL on the other hand, pretends 

 to have freed the geine, by prolonged washing, from the muriatic acid 

 which had served to precipitate it: and to make certain the absence of the 



