372 SCIENCE IN SHORT CHAPTERS. 



in diameter, is fitted with an iron piston. This piston is 

 driven forth by a screw working in a collar at one end of 

 the squirt. Into the other end is screwed a brass nozzle 

 with an aperature about one twentieth of an inch diameter, 

 tapering or opening inwards gradually to the half-inch 

 bore. 



Into this bore I place snow or fragments of ice, then, 

 holding the body of the squirt firmly in a vice, I work the 

 lever of the screw, and thus drive forward the piston and 

 crush down the snow or ice-fragments, which presently be- 

 come coherent and form a half-inch solid cylinder of clear 

 ice. Applying still more pressure, this cylinder is forced 

 like a liquid through the small orifice of the nozzle of the 

 squirt, and it jets or spouts out as a thin stick of ice 

 like vermicelli, or the "leads" of ever-pointed pencils, 

 for the moulding of which the squirt was originally con- 

 structed. 



I find that ice at 32 can thus be squirted more easily 

 than beeswax of the same temperature, and such being the 

 case, I see no reason for imagining any complex operation 

 of regelation in the case of the ice, but merely regard the 

 adhesion of two pieces of ice when pressed together as 

 similar to the sticking together of two pieces of cobblers'- 

 wax, or softened sealing-wax, or beeswax, or the welding 

 of iron or glass when heated to their welding tempera- 

 tures, i.e., to a certain degree of incipient fluidity or vis- 

 cosity. 



If a leaden bullet be cut in half, and the two fresh-cut 

 faces pressed forcibly together, they cohere at ordinary at- 

 mospheric temperatures, but we have no occasion for a re- 

 gelation theory here. The viscosity of the lead accounts for 

 all. At Woolwich Arsenal there is a monster squirt, similar 

 to my little one. This is charged with lead, and, by means 

 of hydraulic pressure, the lead is squired out of the nozzle 

 as a cylindrical jet of any required diameter. This jet or 

 stick of lead is the material of which the elongated cylin- 

 drical rifle bullets are now made. 



But returning to the point at which we started, on the 

 subject of ice, viz., its Alpine accumulation above the 

 snow-line. If the snow-fall there exceeds the amount that 



