INTRODUCTION. 



In the following tables will be found data for the expansion by heat 

 of about three hundred and fifty different substances. In every case 

 the coefficient for one degree is given, a rule which involved many 

 tedious reductions during the process of compilation. It will be 

 noticed that the linear and cubical coefficients are collected separately. 

 This has been so arranged in order to avoid confusion. It would have 

 been easy for the compiler to have given in many cases either the cubical 

 coefficient or the linear coefficient by itself, leaving it to the reader to 

 multiply or to divide by three in order to obtain the other value. But 

 this would have manifestly involved great inaccuracies, since the 

 cubical coefficient is not in every case exactly treble the linear. 

 Accordingly the compiler has in no instance given a cubical value 

 deduced by himself from a linear, or vice versa. Every determination 

 given must rest solely upon the original authority of the experimenter. 

 For errors involved in reducing to the single centigrade degree the 

 compiler is alone responsible. 



One difficulty was encountered in dealing with the expansion rates 

 of liquids ; namely, that the data given were often too full for incor- 

 poration in tables such as these. For instance: in most of Kopp's 

 determinations, the volume of each liquid is given at many temper- 

 atures, say at every five degrees from 0° up to 100° and over. In 

 some cases, even, determinations are given for every degree. In such 

 instances the compiler has simply selected from the list the values 

 at two, three, or four salient temperatures, and has referred to the 

 original paper for the rest. 



For these tables absolute completeness cannot be claimed. Nothing 

 will be found in them relating to the expansion of liquid mixtures or 

 of solutions. In all other directions, however, it is hoped that they 

 will prove practically complete, at least up to January 1st, 1876. 



F. W. C. 



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