1819.] Scientific Intelligence. 295 
meet with copper of even so high a specific gravity as that given 
by Cronstedt, though I have examined the purest copper used 
in this country for alloying gold, and in which I could detect no 
sensible quantity of any foreign ingredient. I was naturally 
anxious on that account to take the specific gravity of the best 
kinds of Japan copper. This I have been enabled to do by the 
kindness of Professor Jameson, who got a piece.of Japan copper, 
said to be of the very best quality, from a gentleman who had 
been in the habit of dealing largely in that article of commerce 
in India, and had himself (for he was the captain of a ship) car- 
ried it from Japan to India in great quantities. I found its specific 
gravity only 8-434, and hence, I think, we may conclude, that the 
number assigned by Cronstedt for the specific gravity of copper 
is above the truth. Bergman’s number, @ fortiort, is also in 
excess. 
IV. Measurement of an Arc of the Meridian in India. 
Many of our readers are probably aware that a trigonometrical 
survey of India has been going on for a good many years, at the 
expense of the British government in that country, and under 
the superintendence of british officers well qualified for perform- 
ing a task of that kind. Lieut.-Col. William Lambton, F.R.S. 
of the 33d reg. of foot, took the opportunity of this survey to 
measure, at different times, an arc of the meridian from north 
latitude 8° 9’ 38” to north latitude 18° 3’ 23:6”, being an ampli- 
tude of 9° 53’ 45”, the longest single arch that has ever been 
measured on the surface of the globe. The full details of this 
great measurement are partly contained in the 12th volume of 
the Asiatic Researches ; and will be partly inserted in the 13th 
volume of that work, which will not probably be published for 
these three or four years. Col. Lambton has inserted an abstract 
of the principal results into a paper, which has been published in 
the second part of the Philosophical Transactions for 1818. 
From that paper I shall take a few of the facts which are most 
likely to be generally interesting to European readers. 
1. The mean length of a degree due to latitude 9° 
re ARK, PTOI, WS ele Me hoo bdo on aye wee oe 60472°83 
The mean length of ditto due to lat. 12° 2’ 55”, is.. 60487°56 
The mean length of ditto due to lat. 16° 34’ 42”, is 60512-78 
Thus we see that these measurements show the degree length- 
ening as we advance towards the pole. In this respect, they 
agree with all preceding observations, which demonstrate that 
the polar axis of the earth is shorter than the equatorial. 
2. Col. Lambton has shown by a comparison of his measure- 
ments with the length of a degree as determined in France, in 
England, and in Sweden, that the compression at the poles 
amguuts to 51, of the length of the axis. 
Vor. XIII. N° LI. i 
