490 
20, 10, 5, 2, I, I kilograms 
500, 200, 100, 100 grammes (hectograms) 
30 Metric | 5° 2% 1% 7° »  (dekagrams) 
Weights ORS » , 
0°5,0°2,0°1,O°1 gramme (decigrams) 
0'05, 0'02, O'OI, O'OI_,, (centigrams) 
.0°005, 0002, o’001, o'‘oo!_ gramme (milligrams) 
( Hectolitre, or 100 litres 
| Demi-hectolitre, ,, 5O ste; 
Double dekalitre, ,, 20, eh, 
Dekalitre, TOs o 
Demi-dekalitre, a Si aes 
13 Metric Measures Ot Bee, By 4 litre 
of Capacity f Demi-litre, zs Os its, 
Doubleidecilitre, .,, .). O'2 . ;, 
Decilitre, rie ovis A 
Demi-decilitre, BA RIOIOSY dies 
Double centilitre, ,, o'02 ,, 
[ Centilitre, EOI! tals 
Total number of metric weights and measures used in 
France and other countries, 49. 
For dry commodities, the demi-dekalitre is the smallest 
measure used. The litre being equal to a cubic deci- 
Fic. rr.—Decimetre and its nearly equivalent length of four inches 
On one plane surface the word “ METRE ” is engraved, 
and on the other “FORTIN A PARIS,” and “ Royal 
Society, 44.” This end-standard was determined to be 
exactly the length of a metre at the temperature of melt- 
ing ice. The other was a line standard, the bar being 
nearly equal in width, but only 5°3 millimetres thick, and 
it is about 4 centimetres longer. On the upper surface is 
engraved “ Royal Society, 45,” and transverse lines,so fine 
as hardly to be seen with the naked eye, are cut about 2 
centimetres from each end for defining the length of the 
metre, as shown in the following figure :— 
The length of a metre is to be taken between the two 
transverse lines at the mid-width of the bar, and it has been 
determined to be less than a metre by 0'01759 millimetre, 
taken at the standard temperature of melting ice. 
On being brought to this country, the two platinum 
metres were carefully compared by Captain Kater with 
the length of 39'4 inches on the Shuckburgh scale, con- 
sidered by him to be the British scientific standard of 
length. Full details of the comparisons made with 
Captain Kater’s microscopical comparing apparatus are 
given in Phil. Trans, 1818. It was required to determine 
the length of the platinum metre at its standard tempera- 
ture of 32° Fahr. in terms of the brass standard yard of 
36 inches at its standard temperature of 62° Fahr. Allow- 
ance was made for the different rates of expansion of 
the two metals, the co-efficient of expansion of the 
platinum being taken to be 0'00000476 for 1° Fahr., 
as determined by Borda, and that of brass o’oooo!o1, 
as found by Kater’s experiments. The length of the metre 
at 32° Fahr. was thus determined from the méfre a bouts 
to be 39'37086 inches of the Shuckburgh scale at 62° 
Fahr., and from the métre a traits 39'37081 inches, after 
allowing for its error = o‘oo069 inch. The mean length 
of the metre was therefore 37°37084 inches of the Shuck- 
burgh scale, and as this scale had been found o'o0005 
inch longer than the Parliamentary standard, the true 
NATURE 
q 
metre, or 1,000 cubic centimetres, in volume, is also equal 
to 1,000 grammes weight of distilled water at its maxi- 
mum density ; consequently the 
Demilitre = 500 cubic centimetres, or grammes 
weight. of water. 
Double decilitre = 200 :; i 
Decilitre = 100 *3 mn 
Demi-decilitre = 50 na i 
Double centilitre = 20 = i 
Centilitre = 10 . as 
There are also graduated measures of 5, 2, and 1 cubic 
centimetres or grammes weight of water. 
The earliest recognition by the British Parliament of 
the metric system thus established in France took place 
soon after the close of the war. On March 15, 1816, Mr. » 
Davies brought forward a motion in the House of Com- 
mons, which was carried, for comparing the imperial 
standard yard with the French standard metre. The 
Government entrusted the necessary operations to the 
Royal Society, who obtained for the purpose two platinum 
metres from Paris. These had been verified by M. Arago, 
by comparison with the French standard. Onewas an 
end-standard, like the “ Metre des Archives,” but was 
nearly twice as thick, being 7°3 milimetres in thickness. 
length of the metre was finally determined by Captain | 
Kater to be 39°39079 British inches. : 
Ever since this period, this authoritative equivalent of 
the metre in imperial measure has been recognised as the 
true equivalent, and it received the sanction of Parlia- 
ment, in the Act of 1864, for legalising contracts made in 
this country in terms of the metric system. It is, how- 
ever, to be observed that it is the sczentific equivalent of 
the metre in imperial measure. For all commercial pur- 
poses, on the other hand, the measure of a metre is 
always used at ordinary temperatures just as a yard 
measure is used, and the comparison of the two should 
therefore be more properly made at the same average 
temperature of 62° F. At such temperature a brass metre 
is equal to 39382 inches, and this length is to be taken as 
the commercial equivalent of the metre in British measure. 
Of course, this difference of the equivalent in imperial 
measure of the metre at its legal and at its ordinary tem- 
perature, amounting only to 77455 inch is perfectly imma- 
terial in commercial measurements of small quantities, 
and the metre may safely be estimated as equal to 398 of 
Be inches, and the decimetre at 3°94 inches, as shown in 
ig. II. 
No satisfactory comparison of the primary kilogram 
with our unit of imperial weight was made until the year 
1844, after the construction of the new imperial standard 
pound, under the authority of the Standards Commission. 
The comparison of the standard units of weight of the 
two countries was then undertaken by Prof. Miller, at the 
request of the Commission. He found that previous de- 
terminations of the weight of the kilogram varied 
amongst themselves from a minimum of 15432°295 gr. to 
a maximum of 15438°355 grains. Under these circum- — 
stances, he proceeded to Paris in the autumn of 1844, and 
obtained permission from the French Government to 
compare the Kilogramme des Archives with our English 
weights. For the comparison, he took with him the Par- 
