96 SCIENTIFIC AMUSEMENTS. 



powdered mass in a bottle. Pour in some ether so as to cover the 

 powder, cork the bottle, and let the whole stand awhile ; the ether 

 will gradually penetrate into the fragments of seed and dissolve 

 out the oily matters therein contained without affecting the rest 

 of the vegetable matter. Now add a little more ether, shake up, 

 and allow to stand awhile to settle ; pour off the ether (through a 

 filter, (Expt. 56), if not clear) into another bottle, and shake up 

 the partly exhausted seeds with some more ether, repeating the 

 operation two or three times in succession, and collecting all the 

 ether poured off in the same bottle. In this way practically all 

 the oily matter contained in the seeds will be dissolved out. 

 Now place the ethereal solution of oily matter obtained in a retort 

 or a flask provided with a cork and bent tube, and connected 

 with a Liebig's condenser (fig. 24), and gently heat the flask so as 

 to boil off the ether and leave the oil in the flask. 



To do this safely, the flask should not be directly heated by a 

 lamp, but should be placed in a pan of warm water, to which a 

 little more hot water is now and then added so as to keep it 

 sufficiently warm to make the ether boil ; if, on the other hand, a 

 flame is placed underneath the flask, there is not only a liability 

 of the flask cracking, and a large mass of flame being produced 

 through the firing of the ether, but, further, there is a possibility 

 of the ether vapour being generated faster than it can be condensed 

 again in the condenser, so that a quantity of uncondensed vapour 

 streams out at the far end ; this being heavy, is apt to flow along 

 the table, and ultimately to take fire at the lamp, thereby produc- 

 ing a body of flame that will probably severely burn the experi- 

 menter, and possibly do other damage. When bottles of ether are 

 unstoppered, especially in hot weather, anywhere near a light 

 (such as a gas or candle flame) similar firing of escaping vapour 

 is very apt to take place ; and many accidents happen through 

 the incautious opening of bottles of ether, or substances containing 

 ether (such as the " collodion " used by photographers), too near a 

 candle. Some very inflammable substances used for burning in 

 lamps, such as "benzoline" and spirits of wine, are liable to 

 produce the same danger, more especially in summer or hot 

 climates (compare Expt. 41). 



For manufacturing purposes on the large scale, ether is too costly 

 for use as a solvent for oils, &c.; cheaper fluids, such as " benzene " 

 (obtained from coal tar), and " bisulphide of carbon," are generally 

 employed, the oily materials to be treated being placed in a kind 

 of tank and the solvent poured on them, and then run away by 

 means of a tap at the bottom of the tank into a kind of boiler 

 heated, not by fire, but by means of a steam pipe, so as to avoid all 



