48 SCIENTIFIC AMUSEMENTS. 



much increased by the operation that the spirit will now readily 

 take fire in a spoon. Almost the whole of the water present can 

 thus be in time removed, leaving nearly absolute alcohol in the 

 bladder. 



Membranes of different kinds are frequently employed to effect 

 a separation of substances from one another when we have mixed 

 together bodies which will pass through the membranes with 

 different degrees of ease (Chapter VIII.). 



Absolute alcohol obtained by any of these processes is a highly 

 inflammable fluid, which readily takes fire if spilt about near a 

 flame. The "methylated spirit" usually burnt in spirit-lamps 

 consists of alcohol not quite absolute (but nearly so), to which a 

 certain amount of a peculiar ill-flavoured spirit-like substance 

 obtained from wood by distillation is added in order to prevent 

 the liquid being used for drinking. The excise duty on potable 

 spirits is extremely high in Great Britain, far above the actual 

 value of the alcohol present, and this prevents the use of pure 

 spirit in this country for many manufactures that can be carried 

 on more cheaply in other countries where the duty is lower ; to 

 diminish the injury to trade thus effected a much smaller duty is 

 levied on "methylated spirit," which, although too badly-flavoured 

 to be drunk as a beverage by most people, is nevertheless applic- 

 able for varnish-making and many other trade purposes almost as 

 well as pure spirit. 



In case of alcohol or methylated spirit being spilt about and 

 taking fire (as for example by upsetting a spirit-lamp), it should be 

 remembered that pouring water on the flames is far less effective 

 than smothering them out by throwing over them a piece of carpet, 

 an old blanket or coat, or any woollen fabric that may be handy : 

 cotton and linen burn so much more readily than wool that they 

 are much less serviceable for extinguishing flames, unless they 

 have been previously wetted ; a wet towel, however, will often 

 suffice to put out a small fire caused by some accident if applied 

 in the very early stages. Lamentable accidents sometimes happen 

 through ladies' muslin dresses and the like inflammable clothing 

 being set on fire ; if in such cases the persons on fire have sufficient 

 presence of mind to lay themselves down and roll over on the 

 carpet whilst calling for assistance, they will often escape serious 

 injury ; any one coming to help should fling a coat, woollen curtain, 

 or carpet, &c., over the burning dress and so smother out the 

 flames. Unfortunately, persons on fire are apt to "lose their 

 heads " and run about shrieking instead of lying down ; this fans 

 the flames and makes them burn far more fiercely, and so the un- 

 fortunate sufferers are far more severely injured than need have 



