206 BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



Expansion Fountain. (Fig. 201, page 205.) This appa- 

 ratus consists of a glass globe with feet, having a cap, stop- 

 cock, and jet, reaching down to the bottom, and an open 

 vessel with cap screwed to the upper end of the cock. To 

 use, the lower vessel is nearly filled with water, and the 

 stop and jet screwed in and placed on the air pump under 

 a receiver ; as you exhaust the air from the receiver, the 

 air in the upper part of the globe is expanded, and the 

 liquid forced through the jet into the upper vessel : in return 

 ing the air to the receiver, the water descends. 



Price, $3.50. 



Three Globe Fountain, by Elasticity. (Fig. 202, page 205.) 

 This consists of a double globe on a foot, with open 

 end, having a jet pipe extending from the bottom of the 

 lower globe to the top of the second, and another globe 

 with a neck covering the jet pipe. To use, fill the lower 

 globe nearly full of water, or a colored liquid, screw in the 

 jet pipe, and cover it with the upper globe ; place it on the 

 air pump and cover with a receiver ; exhaust the air, which 

 removes the pressure from the upper vessels and expands 

 the air in the lower globe, forcing the liquid up the pipe 

 into the upper vessel, and from thence falling into the second. 

 Return the air to the receiver, and the water is forced into 

 the upper vessel, and from thence again into the lower one. 



Price, $2.50. 



Fig ' 21 ' 3 - Lungs Glass. (Fig. 203.) An instru- 



ment or apparatus used with the air pump, 

 intended to prove the elasticity of the air. 

 It consists of a glass globe of about four 

 inches diameter, with a foot to it, and also a 

 brass cap at the top ; within the glass is a 

 small bladder, tied to a short tube, which 

 is attached to the cap, and projects an inch 

 or so within the glass. This tube passes 

 out at the top, and is terminated by a small 

 orifice. The lungs glass is placed under the 

 receiver of the air pump, and as the air is 

 exhausted the bladder collapses ; being admitted it expands 

 again, showing the exact action of the animal lungs in re- 

 spiration. Price, $2.00. 



