Page:Proceedings of the Royal Society of London Vol 1.djvu/205

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185

The result of these experiments was as follows:—

The wootz of the 1st cake reduced 0.139 its own weight of lead.
That of the 2nd ————— 0.125 ————— ———
———— 3rd ————— 0.120 ————— ———
———— 4th ————— 0.156 ————— ———
———— 5th ————— 0.102 ————— ———
Steel containing 1/60 its weight of carbon 0.094 its own weight of lead.
White cast iron —— —— —— 0.228 ——— ———

From these experiments, the author says, it appears, that wootz contains a greater proportion of carbonaceous matter than the common sorts of cast steel, and that some particular cakes approach very near to the nature of cast iron. This, added to the imperfect reduction, seems to him quite sufficient to account for its refractory nature, and for the want of homogeneity in its texture.

Notwithstanding the above imperfections, Mr. Mushet thinks wootz possesses the radical principles of good steel, and that it is impossible not to have a very high opinion of the excellence of the ore from which it is produced; the possession of which, for the fabrication of steel and bar iron, would be an object of the highest importance. It is, he says, a subject of regret that such a source of wealth cannot be annexed to the dominions of this country; as in that case the East India Company might supply their settlements with an article superior in quality, and inferior in price, to any they send from this country.


Abstract of Observations on a diurnal Variation of the Barometer between the Tropics. By J. Horsburgh, Esq. In a Letter to Henry Cavendish, Esq. F.R.S. Read March 14, 1805. [Phil. Trans. 1805, p. 177.]


It appears from Mr. Horsburgh's journal, that in steady weather, within the tropics, a regular elevation and depression of the barometer takes place twice in every twenty-four hours, the greatest depression being about four o'clock morning and evening, and the greatest elevation being from eight in the morning till noon, and from nine or ten in the evening till midnight.

In a letter which accompanies the journal, dated Bombay, April 20th, 1804, Mr. Horsburgh says he has observed, since his arrival in India, that the atmosphere appears to affect the barometer differently at sea from what it does on shore. As a proof of this, Mr. Horsburgh gives a series of observations, made on two barometers, one by Troughton, the other by Ramsden, of which the following is an abstract.

From the time of leaving the Land's End, on April 19th, 1802, the mercury was fluctuating and irregular, till April 29th, lat. 26° N., long. 20° W., when it constantly performed two elevations and two depressions every twenty-four hours. These Mr. Horsburgh calls equatropical motions. From lat. 26° to 10° the difference in the high and low stations of the mercury was not so great as it was from