OF ARTS AND SCIENCES. 391 



It hardly needs to be said, that one can measure the subdivisions 

 with much greater accuracy than it is possible to obtain in making the 

 transfers. 



The following results have been obtained for the errors of sub- 

 division of the various prototypes discussed in this paper. In bar H^ 

 the initial defining line is considered to be at the inch end of the bar. 

 In all the other bars the initial line is the middle defining line of the 

 meter and the yard. In the case of the meter the distances are 

 reckoned as follows : — 



I = distances reckoned from the middle line towards the cm. end. 

 II = distances reckoned from the middle line away from the cm. end. 



For the yard, 



I = distances reckoned towards the inch end. 

 II = distances reckoned away from the inch end. 



The columns under the heading 2 contain the corrections reckoned 

 from the initial line. It is to be remembered that a plus sign indi- 

 cates that the measured space is too short. 



Subdivisions of R^\ 

 (Idiv. = .504;u.) 



Feet. 



Mean of all 

 previous 

 July 17. July 18. Mean. Observations. Adopted Corrections. 2 



1 — l.Odiv. — 1.3div. — l.Gdiv. — O.Odiv. — 1.2diT. —0.6^ — 0.6/* 



2 +6.8 " +6.4 " +6.6 " +4.2 " +5.4 " +2.8 /t +2.2 /t 



3 _4.8 « —5.4 " -5.1 " —3.3 " —4.2 « —2.2/* +0.0 /x 



Three-Inch Spaces of the First Foot. 



July 15. July 15. July 17. July 18. July 19. July 20. July 21. Means. 2 



1 — 6.6div. — 5.4div. — 3.2div. — 2.8div. — 3.6dlv. — 4.3div. — 4.1div. — 4.3div =— 2.2iu. — 2.2/x 



2 +2.9 « +1.0 " -1.3 " +0.3 " -1.0 " +0.9 " +0.9 " +0.2 » = +0.1ft -2.1/u, 



3 _3.o " -2.3 " -1.5 " -3.6 " -2.1 " -3.4 " —2.2 " -2.6 " =: -1.3^i -3.4;ol 



4 +6.8 " +8.6 " +6.0 " +6.4 " +6.7 " +5.7 " +5.5 " +6.8 " =+3.5^t+0.U 



Inches of the First Three-Inch Space. 



