10 



6 = corrected volume of gas taken, after absorbing C0. ; . 



c = contraction after explosion with oxygen. 



d = volume of CO 2 produced by the explosion. 



a-6 = 



d=CO. 



Such is the rapidity with which the analyses are executed 

 that frequently three complete analyses of blast furnace gases 

 have been made in one hour, sometimes four. This form of 

 apparatus is specially adapted for the analysis of blast furnace 

 gases ; but by the aid of the three laboratory vessels on the left, 

 analyses of any mixture can be made. 



The second and third chambers may contain any absorbent 

 material which may be required in other than blast furnace 

 gases. 



17. Hidsdaie's rotary chromometer for testing low 

 carbons by Stead's alkali method. Copper in steel, &c. 

 1886. Exhibited by J. Crosby Robson. 



The apparatus consists of the following parts : 



Three glass tubes of equal bore throughout. The centre one 

 is sealed at the bottom. Each of the outside ones is drawn out 

 fine and prolonged about 3 inches, passing through an india- 

 rubber cork to within ^ inch of the bottom of the bottle. In 

 each tube is loosely fitted a small cylinder, about 1 inch in length, 

 of glazed china clay or porcelain or a sealed glass tube containing 

 white powder. Two syringes, one for each bottle, are connected 

 therewith either directly or by a piece of indiarubber tube, to 

 a short glass tube which just passes through the cork. There 

 is also a third tube with a tap on it which passes from the lowest 

 point of the bottle through the cork, and bends over for about 

 2 inches towards the back of the apparatus. Above the three 

 comparison tubes is a small mirror which can be turned to any 

 angle, so as to enable the operator to see down them. 



On one side is a scale for measuring the height of the column 

 of liquid in the tubes, on the other a pointer which slides on a 

 brass rod. There is a framework of mahogany for the above, 

 the whole of which revolves on a circular bottom weighted with 

 lead. 



The apparatus can thus be readily turned round, for better 

 comparison of colour, &c. without sacrificing its stability. 



Directions for use. 



Fill the centre tube up to 20 divisions with the liquid to be 

 tested. 



The tubes on each side are for the standards which may be of 

 different depths of tint, thus enabling better comparison to be 

 made than if only one standard is used. 



