INTRODUCTION 



The laboratory exercises of the "First Year of Science" are, 

 as the writer stated in the Preface to the text proper, such as 

 can be performed with simple apparatus. To make the work 

 of instruction easier, and to suggest substitutions of simpler 

 forms of apparatus for those of the ordinary type, the following 

 preliminary directions are given: 



1. An alcohol lamp (Exercise 73), a gasoline torch, or even 

 a metal kerosene lamp with a metal chimney, may be used in 

 place of a Bunsen gas burner. 



2. A ring stand can be made, if the laboratory has none 

 (see Fig. 11, Exercise 16), out of telegraph wire and a wooden 

 block. 



3. A test tube holder can be made by folding a strip of 

 paper lengthwise. 



4. The only glass-working called for in these exercises is 

 the bending of glass tubing. Tubing should be heated in a 

 wing top or fish tail flame, if possible. An ordinary gas jet 

 is excellent; so is the flame produced by a wide wick in a 

 kerosene lamp. If an alcohol lamp must be used, the glass 

 should be heated at one spot, then bent a little, then heated 

 close by, and bent a little more, until a rounded bend is 

 produced. If outspread flames are used, the glass should be 

 held lengthwise with the flame. Sharp ends of tubing 

 should be fire-polished, that is, the ends should be held in 

 a flame until the glass just begins to melt. 



5. Pieces of thin sheet glass (squares about 4 inches on a 

 side) do very well as substitutes for watch glasses, if they 

 are laid in a horizontal position. 



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