4- A SIMPLE SPIROMETER. 

 W. G. Tight. 



(Experimented with before the Scientific Association, March 8th, 1890.) 



The api)aratus here described and figured on Plate A, Fig. 5, is 

 one which was constructed for and used by the class in Practical 

 Physiology. The apparatus was constructed for the determination 

 of the vital capacity, supplemental, tidal and compleraental air, also 

 for experiments on the increase of vital capacity by regular exercise 

 of the respiratory mechanism. The results were so satisfactory that 

 it was thought that others might wish to use the same plan, as the 

 construction is very simple. 



A board about 10 in.x 16 in x i in. forms the base ; at the center 

 of one end is braced an upright piece i in.x i^ in.x 28 in.; to this 

 at the top is also bracketed an arm i in.x i;^ in. x 12 in.; a large 

 stone jar is used to hold the water and rests on the base board ; a large 

 glass jar (in our instrument a zoology preserving jar), having a capaci- 

 ty of something over 4,000 c. cm., is graduated from the bottom up 

 into 50 c. cm divisions by adding water and marking the different 

 levels; after this is graduated, a small hole in made with a round file 

 in the bottom of the jar and a rubber tube with a glass mouth piece 

 attached ; the jar is then suspended bottom side up over the w^ater jar, 

 (by three wires which pass around it), by a wire which passes through 

 a small pulley at the end of the arm and then through another nearer 

 the standard and having a weight attached to the end of the wire just 

 etiual to the- weight of the jar ; the rubber tube is provided with a 

 strong thumb clam]j. 



To work the instrument, open the thumb clamp, press the air re- 

 ceiver down into the water jar as far as ])ossible ; then by suction draw 

 the water up into the air receiver until it is full of water. The re- 



