Mr. T. Tate on a new Evaporameter and Absorbometer. 129 



A more delicate instrument, adapted for special purposes, will 

 be hereafter described. 



Absorbometer. 



This instrument is used for determining the volumes of liquid 

 absorbed during successive intervals of time, and generally for 

 finding the rate at which liquids are transmitted through the 

 pores of different absorbents. It consists of a graduated glass 

 tube A B, about T %ths of an inch in the bore and 20 inches long, 

 sustained in a horizontal position by the supports A C and B D, 

 and having one of its extremities bent after the manner shown 

 in the diagram (fig. 2) ; an enlarged tube E, on which is placed 



Fig. 2. 



the absorbent to be examined, polished at its top, which is on a 

 level with the axis of A B, cemented or otherwise attached to the 

 top of the bent tube K ; and a capillary tube J, having its upper 

 end on a level with the upper side of the tube A B, with a funnel- 

 shaped top for supplying the tube with liquid as may be required. 

 The enlarged tube E may be replaced by tubes of different dia- 

 meters and lengths. The whole tube having been filled with 

 liquid, the finger is applied to the extremity A, and a few drops 

 of water are added, so as to cause the water to cover the top of the 

 tube E j the absorbent is then laid on the tube E, the finger 

 being at the same time withdrawn from the extremity A : as the 

 water is being absorbed by the absorbent, the column of water 

 in the horizontal tube A B moves towards B ; and the rate of 

 this motion being observed by means of a watch with a pointer 

 indicating seconds, gives the rate at which the water diffuses 

 itself through the pores of the absorbent; and so on to other 

 cases. The following form of the apparatus was employed when 

 the amount of water diffused or transmitted, as the case might be, 

 was unusually large : — 



A graduated tube, B, fig. 3, about 9 inches long and J of 

 an inch diameter, closed at the top and having a smooth welt at 

 the bottom, — a small perforation, 0, about ^u^h of an inch dia- 

 meter, having been made in the tube at a short distance from its 



Phil. Mag. S. 4. Vol. 23. No. 152. Feb. 1862. K 



