52 THE BOOK OF THE LANTERN. 



nary blow -through, or safety jet, which, on the whole, is 

 the best form of burner for amateurs to adopt (see 



% 21). 



A isja piece of wood rounded off at one side of its upper 

 end, as shown, so as to accommodate its form to the bent 

 blow-pipe, which is marked 0, for this pipe is the conveyer 

 of the oxygen. This is fixed in position by loops of wire, 

 passing through holes in the wooden support. Upon 

 the other side of this support is bound in like manner 

 another blow-pipe, which has its fine nozzle cut off. This is 

 marked H, for hydrogen, and is connected when in use 

 by means of an india-rubber tube, to the house-gas supply. 

 The upper points of these two pipes are so adjusted that 

 the oxygen gas will blow through the flame from the H 

 pipe, on to the lime cylinder L. A jet formed on this 

 principle has the word " safety " linked to it, because the 

 two gases are kept quite separate until they meet at the 

 point of com bustion. Singly, they are innocent of harm ; 

 but mixed, except under certain precautions, as we shall 

 presently see, they form an explosive compound second 

 only to gunpowder. 



To say that the arrangement thus described and illus- 

 trated is anything but faulty in construction would be 

 absurd, but I will say that there are many jets sold of 

 far more pretension which give no better light, and cost 

 as many florins as this one does pence. But as I have 

 said, I have described it as a ready means of explaining the 

 principle of the blow-through jet. I have tried many 

 different patterns of jets, and have selected the one illus- 



