248 M. Carey Lea on a Constant Aspirator and Blower. 



I have found this instrument to be of the greatest utility and 

 convenience; so much so that I have two of them permanently 

 fitted up in my laboratory. One valuable application is for get- 

 ting rid of poisonous vapors. In any distillation, for example, the 

 recipient or Wolf's bottle may be made to ( 



with a chimney, a cork with a tube may t 



) the retort, or an extra tube through the cork of t 

 vhich the distillation is performed, and the flexible tube, 



G I, passed c " ^ " ' ' 



the \ ■ ■ 



passed over it and a current of air be driven through daring 

 vhole operation. Or, if the products of distillation are val- 



: been able to dissolve oxyd of iridium containing 

 osmic acia, m aqua regia, and drive off the osmic acid without 

 suffering any inconvenience from the latter. The chemist Avho 

 has once used this arrangement will find it so simple and effica- 

 cious that he will be led to employ it when manipulating with 

 substances much less deleterious than osmic acid. It is very 

 convenient in operations where chlorine is to be passed over or 

 through substances, especially where the operation requires to 

 be occasionally interrupted to examine the result. 



For driving a blow-pipe, an apparatus of this sort, put together 

 with a bottle and a few pieces of tube, is infinitely more conven- 

 ient than the most expensive and cumbrous table blow-pipe, fed 

 by a double bdlows, especially when it is desired to ignite at 

 high temperatures and for a length of time, the automatic nature 

 of the instrument removing the necessity for working the bellows. 

 A considerable degree of heat is easily obtained. A silver pie(J 

 was laid on a fragment of brick and the flame of a Herapath 

 burner, fed with a stream of air by this instrument, was turned 

 down upon it : the coin withered up immediately. A similar com 

 was easily fused to a bright button in a porcelain crucible heated 

 from below. Thick brass wire was melted off in drops, etc. 



It IS not necessary that the instrument should adjoin the blow- 

 pipe or apparatus for which the air current is wanted. In one 

 of mine, the current produced by the tube A B, two feet lon^ 

 13 carried through tubes about sixteen feet, and might easily be 

 earned further without important loss of power. 



"^^e quantity of . - . - ^' 



I depends of 



sired, but is never large. In an experimental trial it was iuu»- 

 that with a consumption of water of 80 litres per hour, a streani 

 ot air amounting to 400 cubic centimetres per minute couW be 

 maintained or in other words, a cubic metre (about a ton) of 

 water would suffice to keep the apparatus in motion for twelve 

 Houre. This instrument may be appropriately caUed an M^- 



Ptiladelphia, June, 1862. ^ 



