ALKALIMETRY ?3 



instrument is rendered much less liable to injury ; it is generally sold with a separate 

 wooden foot or socket, in which it may stand vertically. 



7. The preceding form of alkalimeter (fig. 23), which I contrived several years 

 ago, will, I think, be found equally delicate, but more convenient still than that of 

 Gay-Lussac. It consists of a glass tube A, of the same dimensions and graduated in 

 the same manner as that of Gay-Lussac ; but it is provided with a glass foot, and the 

 upper part, B, is shaped like the neck of an ordinary glass bottle ; c is a bulb blown 

 from a glass tube, one end of which is ground to fit the neck, B, of the alkalimeter, 

 like an ordinary glass stopper. This bulb is drawn to a capillary point at D, and has 

 a somewhat large opening at E. With this instrument the acid is perfectly under 

 the control of the operator, for the globular joint at the top enables him to see the 

 liquor before it actually begins to drop out, and he can then regulate the pouring to 

 the greatest nicety, whilst its more substantial form renders it much less liable to 

 accidents than that of Gay-Lussac ; the glass foot is extremely convenient, and is at 

 the same time a great additional security. The manner of using it will bo described 

 further on. 



8. Another alkalimeter of the same form as that which I have just described, 



except that it is all in one piece, and has no globular enlargement, is represented in 

 Jig. 24. Its construction is otherwise the same, and the results obtained are equally 

 delicate ; but it is less under perfect control, and the test acid is very liable to run 

 down the tube outside : this defect might be easily remedied by drawing the tube into 

 a finer and more delicate point, instead of in a thick blunted projection, from which* 

 the last drop cannot be detached, or only with difficulty and imperfectly. A glass 

 foot would moreover be an improvement. 



9. With Schuster's alkalimeter (represented in fig. 25), the strength of alkalis is 

 determined by the weight, not by the measure, of the acid employed to neutralise the 

 alkali : it is, as may be seen, a small bottle of thin glass, having the form of the head 

 of the alkalimeter represented in fig. 23. We shall describe further on the process of 

 analysis with this alkalimeter. 



10. The alkalimeter most used now is that known as Mohr's (fig. 26). It consists of 

 a straight graduated tubo, having its lower extremity contracted and drawn out BO as 



