SEDIMENTATION TUBES 9 



over all, consists of a small spring blade with one 

 cutting edge mounted in scales like an ordinary pocket 

 knife. 



2 . For real convenience of work the blowpipe should 

 be mounted on a special table connected up with 

 cylindrical bellows operated by a pedal. That figured 

 (Fig. 12) is made by mounting a teak top 60 cm. square 

 upon the uprights of an enclosed double-action concer- 

 tina bellows (Enfer's) and provided with a Fletcher's 

 Universal gas blowpipe. 



3. An ordinary bat's- wing gas-burner mounted at the 

 far corner of the table top is invaluable in the prepara- 

 tion of tubular apparatus with sharp curves, and for 

 coating newly-made glass apparatus with a layer of 

 soot to prevent too rapid cooling, and its usually asso- 

 ciated result cracking. 



6. Sedimentation tubes 5x0.5 cm., for sedimentation 

 reactions, etc., and for containing small quantities of 

 fluid to be centrifugalisde in the haematocrit. These 

 are made by taking i4-cm. lengths of stout glass tubing 



FIG. 12. Glass blower's table with Enfer's foot bellows. 



of the requisite diameter and heating the centre in the 

 Bunsen or blow-pipe flame. When the central portion 

 is quite soft draw the ends quickly apart and then 

 round off the pointed ends of the two test-tubes thus 



