powerful, owing to the partial mixture of air before the blast 

 begins to act. 



46. Low temperature gas burner, to dispense with 

 drying closets, sand and water baths, and adapted for 

 drying, evaporating, boiling, &c. 



1876. Exhibited by Thomas Fletcher. 



This burner gives a range of temperature from a gentle 

 current of warm air without visible flame to clear red heat, and 

 is so perfectly under control that a common glass bottle may be 

 placed on a tripod, and heated to the required temperature, with- 

 out risk of fracture. 



For very low temperatures, the ring must be lighted through 

 the lowest opening. This gives a steady current of heated air 

 through the gauze above. For boiling, &c. a light must be 

 applied on the surface of the gauze, thereby providing a large 

 body of blue flame, which can be urged by the blast-pipe until it 

 gives a clear red heat. 



47. Gas burner with stopcock and small wood platform 

 round tube, which has a flat opening, and gives flame 

 suitable for use with mouth blowpipe. Price 4s. Bunsen 

 gas burner to give a flame 6 in. broad, and suitable 

 for heating tubes. Price 8s. 6d. 



1886. Exhibited by Townson fy Mercer. 



48. Hot blast blowpipe, for temperatures up to the 

 fusion of platinum. 



1876. Exhibited by Thomas Fletcher. 



The air jet in the above is coiled round the gas pipe in a 

 spiral form, and both are heated by three Bunsen burners under- 

 neath, which are controlled by a separate tap. By this arrange- 

 ment the power is double that of the ordinary blowpipe. When 

 the jet is turned down to a small point of flame, it will readily 

 fuse moderately thick platinum wire. 



49. Automaton blowpipe on stand for jets not exceed- 

 ing -J in. bore. Price 10s. 



1884. Exhibited by Thomas Fletcher. 



50. Foot blowpipe, ordinary type, with universal 

 motion. Price 15s. 



1886. Exhibited by Toivnson fy Mercer. 



51. Apparatus for drying in vacuo. 



Presented.- by Prof. Markownilcqff, Moscow. 

 B. 488. 1877. 



