HARD WICKE' S S CIENCE- G SSIP, 



hole through with a sharp knife, making it just a 

 shade smaller than copper tube, fix the cork in the 

 hole of the box underneath, and push in the copper 

 tube, which should be attached to the rubber-tubing. 

 Do the same by the hole in the top of box, inserting 

 cork and copper tube as before, to which must be 

 fastened another piece of rubber tubing, carrying it 

 up under the table, and bringing it through a hole in 

 the front of the table, a little way. 



Fix your blowpipe in this tube, inserting a cork if 

 not fitting tightly enough. 



The blowpipe can now be made firm by fastening 

 an upright of wood on the top of the table, and 

 fastening the blowpipe to it by bending wire nails 

 round. We have now a hole left in the side of the 

 box. 



Now what we want is a bag to contain the supply 

 of air necessary to keep the blow-pipe in full swing. 



When you can obtain a nice continuous stream of 

 air, proceed as follows : 



Obtain a spiral spring and fit between handles of 

 bellows. Or to the staple tie a piece of cord, bring 

 it to the top of the table, pass it over a small pulley, 

 and attach a heavy weight. Now for the pedal ; to 

 the staple on under side of handle of bellows attach 

 another piece of cord and fasten it to the end of a 

 strip of wood, broad enough to place the foot on. 

 You will now find that after you have pressed this 

 with your right foot, on the pressure being relaxed, 

 the bellows will be expanded by the weight attached 

 to the cord. 



Of course they are thus filled with air. It will be 

 rather awkward at first to continue the pedalling, 

 but you will soon get used to it, and once you get 

 the bladder filled, a steady continuous motion keeps 

 a nice flame. You can, if you like, weight the 



Fig. 2. — A, Cork ; B, Cop- 

 per tube ; c, India- 

 rubber tube. 



Fig. I. — Foot- working Blow-pipe, a, bottom shelf; b, top shelf; c, bellows ; d, strip of wood nailed 

 on handle of bellows ; ee, pulley wheels ; F, weight ; G, pedal for foot ; H, air chamber ; k', foot- 

 ball bladder ; l, blow-pipe ; m, upright of wood ; n, hole in table ; oo, copper tubing ; p, cord. 



The bag to produce this must of course collapse by 

 cts own elasticity or by weights judiciously placed. 



The best and most easily obtainable is a common 

 football bladder. Fix the nozzle over a copper tube 

 and cork it in as you did the other tubes, allowing 

 ■room for the bladder to expand without coming in 

 contact with sides of box. 



You will now find, if you have followed instruc- 

 tions, that if you blow the bellows with your hand, 

 the bladder will fill ; once filled, a steady motion with 

 the bellows, never jerky, will keep a constant stream 

 of air issuing from the blowpipe ; when the blowing 

 is stopped, a stream of air will continue to flow from 

 pipe till the bladder is exhausted. 



If the bladder soon collapses after the blowing is 

 stopped, the wind is escaping somewhere other than 

 through the nozzle of blowpipe. Light a candle 

 and go all round joints, &c., and you will soon find 

 out where. Remedy : stop up with putty or pitch, 

 and do not use the machine again till thoroughly set. 



bladder, by tying weights at each end of a cloth, and 

 arranging it nicely over the bladder. This will give 

 you a stronger blast of air, but the pedalling wiU be 

 much harder, because the bladder empties much mere 

 quickly, and also takes more pressure to keep it 

 filled. 



I think there is nothing more to say now. Its use 

 being too well known by mineralogists, &c., except 

 that with care, a flame eight or nine inches long is easily 

 obtainable with a wax candle. All kinds of glass- 

 ware for naturalists can be made with a very small 

 amount of trouble, such as dipping-tubes, test-tubes, 

 capillary-tubes, tubes for collecting small insects, 

 &c., funnels, and a host of other similar articles, of 

 which I hope to say further in another paper if the 

 Editor can spare me space. 



As it is I am afraid I have taken up too much room 

 already, but if any one not quite seeing principle, will 

 write to me (address with Editor), enclosing stamped 

 envelope for reply, I will give further information. 



