ANNUAL ADDRESS OF THE PRESIDENT. LI 
perative, but the French academicians were well aware of its defects 
and took precautions to guard against them. 
The first toise copied from the étalon of the Chatelet for scientific 
purposes was that used by Picard in his measurement of a degree of 
the meridian between Paris and Amiens.’ It was made about the 
year 1668, and would doubtless have become the scientific standard 
of France had it not unfortunately disappeared before the degree 
measurements of the eighteenth century were begun. The second 
toise copied from the étalon of the Chatelet for scientific purposes was 
that used by Messrs. Godin, Bouguer, and La Condamine for meas- 
uring the base of their arc of the meridian in Peru. This toise, 
since known as the toise du Pérou, was made by the artist Langlois 
under the immediate direction of Godin in 1735, and is still pre- 
served at the Paris Observatory.’ It is a rectangular bar of polished 
wrought iron, having a breadth of 1°58 English inches and a thick- 
ness of 0°30 of an inch. All the other toises used by the Academy 
in the eighteenth century were compared with it, and, ultimately, it 
was made the legal standard of France by an order of Louis XV, 
dated May 16,1766. As the toise of Peru is the oldest authentic 
copy of the toise of the Chatelet, the effect of this order was simply — 
to perpetuate the earliest known state of that ancient standard. 
The metric system originated from a motion made by Talleyrand 
in the National Assembly of France, in 1790, referring the question 
of the formation of an improved system of weights and measures, 
based upon a natural constant, to the French Academy of Sciences ; 
and the preliminary work was entrusted to five of the most eminent 
members of that Academy—namely, Lagrange, Laplace, Borda, 
Monge, and Condorcet. On March 19, 1791, these gentlemen, to- 
gether with Lalande, presented to the Academy a report contain- 
ing the complete scheme of the metric system. In pursuance of the 
recommendations in that report, the law of March 26, 1791, was 
enacted for the construction of the new system, and the Academy 
of Sciences was charged with the direction of the necessary opera- 
tions. Those requisite for the construction of a standard of length 
were: 
1. The determination of the difference of latitude between Dun- 
kirk and Barcelona. 
15, Art. 4, p. 15. 214, p. 487 and 46, p. C.2. 
