386 
NATURE 
| Sep¢. 11, 1873 
Northern Boundary Commission, engaged in the survey 
of the 49th parallel from the Lake of the Woods to the 
crest of the Rocky Mountains. Archibald Campbell, of 
Washington, is the commissioner in charge; Major 
Twining is the chief of engineers on the part of the 
United States, and Dr. Elliott Coues of the U.S. army is 
the naturalist of the expedition, The British Govern- 
ment details its proportion of the party, which is tho- 
roughly equipped for this service. The operations of the 
present year extend westward from Pembina. 
The expedition under Major J. Powell, to the canons 
of Colorado, is still in the field. Major Powell has spent 
several years in explorations in this region, and has con- 
structed a map of great interest and accuracy. His 
ethnological researches among the Piute and other Indian 
tribes have resulted in a large and exceedingly valuable 
collection, 
Mr. Wm. H. Dall, well known by his elaborate work 
on the Territory of Alaska, founded on his former three 
years’ residence in that region, is now. actively employed 
in continuing his survey and hydrography in the Aleutian 
Islands, under the direction of the U.S. Coast Survey, a 
work on which he has been engaged during the past two 
years. His labours have been principally in Alaska and 
the adjacent islands, from which he returned last Septem- 
ber, having gone there in the summer of 1871. He spent 
last winter in San Francisco, in preparing for the expe- 
dition of the present year, which included fitting out a 
vessel expressly for this service. Among other objects 
contemplated is the selection of an island on the western 
extremity of the Aleutian chain, to serve for the landing 
of the Japan cable, for laying which the U.S. steamer 
Narragansett has been detailed to make deep-sea sound- 
ings. Mr. Dall is assisted by Prof. Baker, of Ann Arbor, 
Mich., astronomer. 
Mr. Henry W. Elliott is at the head of a private expe- 
dition to St. Paul and St. George, the fur-bearing seal 
islands of Bering’s Sea. He has the assistance of Captain 
Bryant, who is in charge of the U.S, Revenue and other 
Government interests on these islands. Mr. Elliott is 
making exhaustive collections in natural history, which 
he sends to the National Museum at Washington, his 
investigations respecting seals and walruses being espe- 
cially valuable and complete. His labours during 1872 
were demonstrated by twenty large boxes of collections. 
He is a very skilful draughtsman, and his drawings of 
natural subjects are remarkable alike for accuracy and 
vigour. 
ON THE SCIENCE OF WEIGHING AND 
MEASURING, AND THE STANDARDS OF 
WEIGHT AND MEASURE * 
Ve 
1V.—The Metric Systent 
AP a system of weights and measures, constructed on 
strictly scientific principles, the metric system may 
justly claim pre-eminence over all others. It was estab- 
lished upon the fundamental basis of the me¢re, its primary 
unit of length bearing a determinate decimal ratio to one 
of the largest natural constants, that is to say, the ten- 
millionth part of the earth’s meridian-quadrant. It in- 
cludes a fixed relation between the units of weight and 
capacity, the 4é/ogrammie and the /itre, and the unit of 
length, the ze¢re, from which both are derived; and it 
comprehends a uniform decimal scale of multiples and 
parts of these units. It must, however, be admitted that 
the more recent progress of modern science has demon- 
strated that the actual standards of metric length, weight, 
and capacity do not exactly correspond with their scien- 
tific definition ; and apart from the insuperable difficulties 
which have been found to exist in the precise determina- 
* Continued from p. 379. 
tion of material standards from any natural constant, the 
unanimous opinion of several of the highest scientific 
authorities in this country has been deliberately expressed 
that there is no practical advantage in adopting a unit 
founded in nature over one of an arbitrary character. In 
truth, the great advantage of the metric system consists 
in the simplicity and uniformity of its decimal scale, and 
the great convenience of this scale for all purposes of 
account as agreeing with the decimal system of notation, 
and more especially when combined with a decimal 
coinage which formed part of the original scheme. These 
undoubted advantages have proved the chief recommen- 
dations to the adoption of the metric system, first by 
France, and afterwards by so many other countries, and 
generally in the scientific world. There is now every 
prospect of the metric system being generally adopted in 
all countries of the civilised world, thus greatly enhancing 
its value as a common international system of weights 
and measures, and constituting, as it were, a universal 
language for expressing all quantities weighed or mea- | 
sured, 
The original steps which led to the establishment of 
the metric system in France were taken with a view of 
reforming the old French system of weights and measures, 
which had become intolerable from their defective state 
and want of uniformity. In 1790, on the motion of M, 
Talleyrand, in the National Assembly, the question o 
the formation of an improved system to be based upon a 
natural constant, was referred to the French Academy of 
Sciences. A request was also made at the same time to 
the British Government that the Royal Society should 
act jointly with the French Academy, but no response 
was given to the invitation, in consequence of the distrust 
then entertained in this country at the progress of the 
revolutionary party in France. The preliminary work 
was consequently entrusted to five of the most eminent 
members of the French Academy, Lagrange, Laplace, 
Borda, Monge, and Condorcet. The important Report of 
this Committee, which bears also the signature of a sixth 
member, Lalande, gave rise to the metric system. It 
was presented to the Academy on March 19, 1791, and is 
printed at length in their Memoirs. The choice of the 
fundamental unit of the new system lay in its derivation 
either from the length of the seconds-pendulum, of the 
earth’s equator, or of the earth’s meridian. The Com- 
mittee rejected the length of the pendulum beating 
seconds as the basis of the new standard unit of length, 
because it involved a heterogeneous element, that of time, 
as well as an arbitrary element, the division of the day 
into 86,400 seconds. They proposed a unit of length 
taken from the dimensions of the earth itself, and not 
dependent upon any other quantity ; and they did not 
hesitate to select as its basis the quadrant of the meridian 
in preference to a quadrant of the equator, from its being 
a universal measure applicable to all countries, as every 
country was placed under one of the meridians of the 
earth, whilst only few countries are under the equator, 
They considered also that no greater dependence could 
be placed upon the regularity of the equator, than upon 
the equality or regularity of the several meridians, They 
recommended the ten-millionth part of the quadrant of 
the meridian as the definition of the new fundamental 
unit of length. Renouncing the ordinary subdivision of 
the meridian-quadrant into degrees, minutes, and seconds, 
they proposed a uniform decimal scale as practically the 
best, from its agreeing with the scale of arithmetical nota- 
tion. In order that no other arbitrary principle should 
be introduced into the new system of weights and mea- 
sures, they recommended for the basis of the unit of 
weight a measured quantity of distilled water, being a 
homogeneous substance, always to be easily found in the 
same degree of purity and density ; and that such quantity 
should be weighed in a vacuum at its temperature when 
passing from a solid to a liquid state. 
