Translation from the Astronomical Jour, of Hamburgh, 231 



(iron=0,0012534363 



^brass=0,001 891 6254 

 the length of the meter was determined to be 39,381022708 

 inches of the scale, which, as the standard temperature of 

 the English measure is 62" Fah. gives the length of the me- 

 ter in English inches 



39 381022708 



= 1,000315270 9=^^-^^^^^ ^"^^^' E"§^''^- 

 The two copies of meters give less, (0,001 inch,) but these 

 were compared with both : the scale of Troughton in Amer- 

 ica, and that which this artist himself uses in London, and 

 had upon both very nearly the same length ; whence it may 

 be concluded, that both English scales agreed very nearly. 

 Thus according to Mr. H.'s comparison the meter is 39,36861 

 English inches : according to the comparison of two other 

 copies by Kater =39,37079. According to Vol. 111. of 

 Base du Systeme Metrique, page 369, the meter of platinum 

 was =39,382755 ; that of iron =39,382649 : both measur- 

 ed upon the brass scale of Mr. Pictet, reduced to the tem- 

 perature of melting ice; at a mean =39,3827, which, ac- 

 cording to Borda's expansion for brass, (0,001783,) by which 

 the experiments made in Paris were reduced to the point of 

 melting ice, from a temperature =12°,75 centigrade, at which 

 they were made, gives 39,37100. The two last comparisons 

 agree very nearly, and their difference lies entirely within 

 the limits of the uncertainty of the thermometrical influ- 

 ence. The authentic meter of Mr. H. appears, however, 

 really to be shorter, though it could be brought nearer to 

 the others by accepting other proportions for the expansion 

 of metals.* This, however, appears not to be allowable, 

 when the results of different comparisons are to be collected; 

 for the determination of the expansion is as important as the 

 comparison itself; therefore, each observer must remain an- 

 swerable for that one which he adopts. I think it should be 

 enquired whether two metals of the same chemical compo- 

 sition, have always the same proportion of expansion ; or if 



* The meter used by Mr. Hassler in liis comparisons, and which the Cheva- 

 lier Bessel suspects to have been too short, was an 07'igmal issued by the 

 French commission, and is therefore far more authentic than the copies used 

 by Kater. We are happy, however, to be able to state, that Mr. Hassler has 

 recentlj' been engaged at Washington in further comparisons, and will proba- 

 bly make his results public in a short time. They are said fully to confirm hi* 

 former experiments. 



