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XXIII. 



A NEW PRINCIPLE IN BLOWPIPE CONSTEUCTION. 



By H. G. BECKEE, A.E.C.Sc.L, A.IC, 

 Demonstrator in the Eoyal College of Science, Dublin. 



Read Apuil 26. Published August 19, 1921. 



The design of a blowpipe which will be suitable for glass-blowing either in 

 chemical and physical laboratories or on a commercial scale, is a matter which 

 does not seem to have received the amount of attention it deserves. Though 

 there are many forms of quick-change blowpipes in existence which are 

 supposed to operate with great ease, none of them that have come to the 

 writer's notice will opeiate really satisfactorily over the wide range of work 

 usually required of such an instrument, even when used with a foot-bellows, 

 and when used with a power-blower they become still less efficient. 



This seems to arise from the fact, which instrument-makers appear to 

 have overlooked, that a blowpipe which is to be used with a power-blower 

 must be differently designed from one to be used with a foot-bellows, if it is 

 to give satisfactory service. This oversight has led to an ei'roneous conclusion 

 which is frequently seen stated, even in quite modern text-books on glass- 

 blowing — namely, that the foot-bellows is preferable as a source of air to a 

 power-blower, owing to the greater control it gives the worker over the flame. 

 It is now generally conceded, however, that the power- blower enables a greater 

 amount of work to be done with less practice, even with an ill-designed blow- 

 pipe, owing to the fact that the attention of the worker is not diverted by the 

 working of a bellows. 



It has long been the opinion of the writer that the inconvenience which 

 arises in the use of existing types of blowpipes is due very largely to the 

 fundamentally wrong design and construction of these instruments, and can 

 only be remedied by bringing the design moie into line with theoretical 

 considerations. 



Although the problem has been worked at from this point of view, the 

 chief practical considerations have also been kept in view, namely, that (1) 

 the blowpipe should give a great range of flames with the minimum of 



