224 



Fiff 23 — Automatic Burette. 



burette is automatically 

 filled to the zero point. 

 When the tap is turned the 

 liquid runs out, air bubbling 

 in from the stock bottle, 

 and measured quantities 

 may be taken. After the 

 liquid has been run out as 

 far as desired, the tap is 

 turned, and the liquid 

 enters the burette. 



The liquid in the air 

 chamber is forced back 

 into the stock bottle, and 

 the burette automatically 

 fills itself. 



The burette can be made 

 of 9 c.c. capacity, but it is 

 much quicker to employ a 

 graduated burette of much 

 larger capacity than any 

 form of automatic measur- 

 ing apparatus. 



The advantages claimed 

 for the burette are — 



(1) Automatic filling to zero 

 point. 



(2) One turn of the tap only- 

 required to fill and to measure. 



(3) Impossibility of spilling 

 corrosive liquids. 



(4) Saving of time, as the 

 filling is done while other 

 operations are conducted. 



Chemicals. — Commer- 

 cial sulphuric acid con- 

 taining 96 per cent. HgSOj, 

 which has a specific gravity 

 of 1-842 at 15-5° C. (60° F.). 

 Owing to the fact that 

 strong sulphuric acid has 

 a somewhat anomalous 

 specific gravity, it is not 

 advisable to test the specific 

 gravity directly. The fol- 

 lowing test will give good 



