10 STATE OF AGGREGATION. 



which remains in the borer is then removed by the small brass rod 

 a (fig. 10). Blunt borers may be sharpened by applying a flat 

 file outside and a round one inside the edge. Such a round file, 

 called a ' rat-tail,' is also often useful for making the holes smoother, 

 or it may serve for widening a hole, which has been simply made 

 with the bradawl, to the required size. The tubes which are to be 

 passed through the cork should be greased or oiled, and the hole 

 should be just so wide as to allow the tube to be pushed in without 

 the risk of breaking. 



3. Solid, Liquid, Gaseous Bodies. State of Aggrega- 

 tion. Many bodies (such as wood, iron, stone, etc.) 

 have a definite form or shape, which can only be altered 

 by considerable force. These are called solid, or better 

 rigid bodies. Those bodies which are usually called 

 liquids, as water, oil, etc., change their form if trans- 

 ferred from one vessel into another; they have not an 

 unalterable form, but immediately take that of the 

 vessel in which they happen to be placed. Liquids 

 show, however, a tendency to assume a definite form, 

 namely that of globular drops. This may be observed 

 when small portions of a liquid are allowed to run 

 slowly from a vessel, or, better still, when one liquid is 

 kept suspended in another. Olive-oil is not so heavy 

 as water, it swims upon it ; and alcohol, or spirits of 

 wine, is still lighter than oil. Alcohol and water may 

 be mixed, while oil does not mix with either. A. 

 mixture of alcohol and water may then be made which 

 is exactly as heavy as the oil, and in which the latter 

 neither sinks nor rises to the surface. A small 

 quantity of oil is placed upon water by means of a thin 

 rod of glass or wood, and ; while the liquid is frequently 

 stirred, alcohol is added until it is found that the small 

 globules of oil neither sink nor rise. About equal 

 quantities of water and alcohol are required for 





