THE PRESERVATION OF MARINE OBJECTS 77 



The glass tubing may be cut into convenient lengths by giving 

 a single sharp stroke with the file, and then pulling it apart with, 

 at the same time, a slight bending from the cut made. 



Cut a piece of tubing about eight or nine inches long, heat it 

 in the blowpipe flame, turning it round and round all the time, 

 until it is quite soft, then remove it from the flame and 

 immediately pull it out sloivly until the diameter in the middle 

 is reduced to about a sixteenth of an inch (fig. 41, 2). Make a 



Fio. 41. SHOWING THE DIFFERENT STAGES IN THE MAKING OP A SHALL 

 SPECIMEN TUBE 



slight scratch with the file at the narrowest part, and divide the tube 

 at this point (fig. 41, 3). Now heat one of these pieces of tubing as 

 before just at the point where the diameter of the drawn part begins 

 to decrease ; and, when very soft, pull it out rather quickly while 

 it is still vn the flame. The part pulled now becomes completely 

 separated, and the tube is closed, but pointed. Continue to heat 

 the closed end, directing the flame to the point rather than to the 

 sides, until the melted glass forms a rather thick and flattened end; 

 and then, immediately on removing it from the flame, blow gently 



