330 nature's teachings. 



which is forced through the tube into the globe, producing 

 beautifully clear and well-flavoured coffee. 



Surgery employs the weight of the atmosphere in the 

 operation called " Cupping/' now rarely employed, but for- 

 merly in such constant use that scarcely any man who had 

 attained middle age had not undergone it. The operation was 

 intended for the purpose of removing the blood from some 

 definite spot. Persons, for example, who appeared to have a 

 tendency to apoplexy were regularly cupped between the 

 shoulders twice a year, i.e. in the spring and autumn. 



The mode of performing the operation is as follows : — A 

 vase-shaped glass vessel called a cupping-glass is placed close 

 to the skin. The flame of a spirit-lamp is then introduced for 

 a moment in the glass so as to expel the air, and the glass 

 is rapidly placed with its mouth downwards on the skin. 

 If this be done with sufficient rapidity, the partial vacuum 

 in the cupping-glass causes it to adhere to the skin, which is 

 forced into it by atmospheric pressure, as shown in the illustra- 

 tion. The blood is, of course, drawn towards the surface by the 

 same means. 



The glass is then quickly removed, and a little brass instru- 

 ment applied, which, at the touching of a spring, sends out a 

 number of small lancet-blades so formed as to make very 

 slight cuts, The glass is again applied, and rapidly becomes 

 filled with blood from the cuts, the air having forced it in 

 exactly as it forces the coffee in Napier's machine. 



In the upper right-hand corner of the illustration is shown 

 the Pneumatic Peg, a comparatively recent invention, and 

 useful in cases where much strength is not required. The base 

 of the peg is fitted with a sort of cup made of india-rubber. 

 When this base is pressed against a smooth and flat surface, 

 such as a pane of glass, the air is forced out of the cup, and a 

 vacuum formed. The pressure of the atmosphere then causes 

 the cup to adhere to the glass with sufficient force to enable 

 objects to be suspended from it. 



The boy's well-known toy, the Sucker, is made on exactly the 

 same principle. A piece of leather, generally circular, though 

 the shape is not of much consequence, has a hole bored through 



