10 



67. Glass condenser, consisting of three equal-sized 

 bell-glasses connected by ground necks, holding about 

 2,000 c.c. 



Made ~by Warmbrunn, Quilitz. fy Co., Berlin. 

 E. 170. 1877. 



68. Fractional distillation tubes, two forms, one with 

 five and the other with six bulbs. Prices 5s. and 8s. 



1886. Exhibited by Townson Mercer. 



These tubes are used in separating a liquid of a low boiling 

 point from a liquid of a higher boiling point. The tube is 

 inserted through a cork in the neck of the flask in which the 

 liquids are boiling. A thermometer is inserted in the other end 

 of the tube. The temperature should be kept intermediate 

 between the boiling points of the two liquids, the vapour of th^ 

 liquid of lowest boiling point passes off through the side tube 

 at the top and may be condensed and will be found nearly pure, 

 because in the upper bulbs there will be found to be only a very 

 small amount of the liquid of highest B.P., and consequently 

 this liquid on evaporating from the bulb will give a purer 

 vapour than if it had largely been contaminated with the liquid 

 of higher B.P. The series of bulbs give every opportunity for 

 the vapour of the liquid of higher B.P. to condense, when it runs 

 back to the flask, either through the side tube or from bulb to 

 bulb. 



69. Specific gravity bottle, 10 grammes, stoppered by 

 a funnel-shaped stopper. Price Is. 



1886. Exhibited by Toiunson fy Mercer. 



70. Specific gravity bottles : 1,000 grns., globular 

 form, price 2s. ; 1,000 grns., Regnault's, price2s. 6d. ; 100 

 grammes with thermometer, price 5s. 



1876 and 1886. Exhibited by J. Orme $ Co. 



71. Sprengel's specific gravity tube. Used as an ordi- 

 nary specific gravity bottle, but being more easily filled by 

 aspirating the liquid into it and completely filling each 

 time. This tube is also used as a stoppered U-tube for 

 gas absorption. Price Is. 6d. 



1886. Exhibited by Townson fy Mercer. 



72. Weighing bottles (2). Prices 7d. and Is. 



1876. Exhibited by J. Orme $ Co. 



73. Hofmann's apparatus showing that in the syn- 

 thesis of water two volumes of hydrogen unite with one 



