J. B. James — Compensation in Chronometers. 



s worthy of note. And it is therefore s 

 t Urdu should not pass unnoticed in 

 dch will occur in January, 1878, and v 

 of the 12-7 magnitude. 



vatory of Hamilton College, Jan. 6, 1817. 



by 



" Foe one to know, is nothing, unless others also may know," 



is an aphorism of modern progressive science; for it is only 



from what has been attained that stop by step further progress 



may be made. This it is which impels the writer to offer some 



if ions on the principles of compensation in chronome- 



It may be assumed as an axiom of general application, that 

 an error sliould be avoided whenever it is possible, rather than 

 compensated ; yet this plain axiom is disregarded in the com- 

 pensation balance, in two respects 



1st. What is the action of the laminated rim as affected by 

 change of temperature? The end of the arm is commonly re- 

 garded as a fixed point, which it is not; for its distance from 

 the center is changed by change of temperature ; and whatever 

 weight is here, if its distance from the center is changed, that 

 change must be compensated at the other end of the segment ; 

 and therefore this is not the place for mean-time screws; while 

 between these two ends of the segment, there must be a point 

 whose distance from the center undergoes little or no change, 

 and where its weight requires no compensation for change of 

 temperature. This point of uniform distance from the center, 

 when ascertained, should therefore be regarded as the fixed 

 point; and if the compensation required were only for the 

 changes in the balance itself, it would be absolutely perfect ; 

 for as the one end of the segment recedes from the center, the 

 other approaches it— the one merely taking the place of the 

 Other; and this would be in effect true whether the ends were 

 equidistant t nt w- 1 point or not— the longer segment re- 

 quiring only the less weight. It is the attempt to compensate, 

 in the balance, for changes in the length and elasticity of the 

 v for a secondary compensation. 

 Thisprin sbeeuprao- 



fcksedin | ss, by Henry 



B. James, of Trenton N. J, for some years. He attaches the 

 outer end of the balai, - r ie arm of a laminated 



convolute, which, at the samelime that it compensates, more or 



