THE ART OF WEIGHING AND MEASURING. 005 



F. Baily ami Doiikin ; and with Katei's lioyal Society yard by Cai)taiii 

 Kattn- in 1831, On October 10, 1834, the Imperial standard (Bird's 

 standard of ITOO) was destroyed by the burnin,i;- of tlie houses of Parlia- 

 ment, in which it was lodged, and very soon thereafter the I^ords of the 

 Treasury -took measures to recover its length. Preliminary inquiries 

 were begun on ]\lay 11, 1838, and on June 20, 1843, they resulted in the 

 ai»[)ointment of a commission to superintend the construction of new 

 Parliamentary standards of length and weight; among whose members 

 the Astronomer Royal (now Sir George B. Airy), Messrs. F. Baily, 

 K. Sheepshanks, and Prof. W. H. Miller were prominent. The labori- 

 ous investigations and experiments carried out by that commission can- 

 not be described here, but it will suffice to say that for determining tlie 

 true length of the new standard Mr. Shee[)shanks employed a pro- 

 visional yard, marked upon a new brass bar designated " Brass U," 

 which he compared as accurately as possible with Sir George Sliuck- 

 burgh's scale, the two Ordnance yards, and Kater's Royal Society yard. 

 The results in terms of the lost Imperial standard were as follows : 

 Brass l>ar*2 = :5(). 000084 from couiparison with Sbuckbmgh's scale, 0-36 inch. 



:W. 000280 from comparisoa with Sbuckburgli's scale, 10-46 inch. 



36. 00030.{ from comi)arisou with the Orduauce yard, I A. 



36.000275 from compari.soii with tbo Orduaiico yard, 2A. 



36. 00022'.) from Cai)taiii Kater's Royal Society yard. 



Jloan = 36. 000234 

 Respecting this mean Mr. Sheepshanks wrote : " This should be 

 l)retty near the truth; but I prefer 36.00025, if in such a matter such a 

 difference be worth notice. 1 propose, therefore, in constructing the 

 new standard to assume that — 



" Brass bar 2= 36.00025 inches of lost Imperial standard at 62° Fabr." 

 And upon that basis the standard now in use was constructed.* 



Turning now to the French standards of length, it is known that the 

 ancient toise de magons of Paris was probably the toise of Charle- 

 magne (A. D. 742 to 814), or at least of some Emperor Charles, and 

 that its ('talon was situated in the court-yard of the old Chatelet, on the 

 outside of one of the pillars of the building. It still existed in 1714, 

 but entirely falsified by the bending of the npper part of the pillar. 

 In 1G68 the ancient toise of the masons was reformed by shortening it 

 five lines; but whether this reformation was an arbitrary change, or 

 merely a change to remedy the effects of long use and restore the etalou 

 to conformity with some more carefully preserved standard, is not 

 quite clear. f These old Jffj/oM.s- were iron bars having their two ends 

 turned up at right angles so as to form talom^-A\u\ the standardizing of 

 end measures was effected by fitting them between the talons. Being 

 placed on the outside of some public, building, they were exposed to 

 wear from constant use, to rust, and even to intentional injury by ma- 



45, p. 664. 1 1, p. 536 and 2, p. 395. 



