APPENDIX No. 6.

Quantity of Iron made in Great Britain in 1839, as stated by David Mushet, Esq.

Production of Iron in Great Britain in the year 1840, as ascertained by Mr. William Jessop, of the Butterley Iron Works, Derbyshire.

Of the above 402 furnaces, there were using hot air, 162; cold air, 240.

APPENDIX No. 8.

Iron Steam-Vessels being built in the Clyde during the Spring of 1846.

1 of 2,000 tons burthen and 750 horse-power.

Quantities of British Iron exported, with the declared value of the same, and the average value of each ton exported in each year from 1827 to 1845 inclusive, stated in tons.

.* Including the kinds stated in the previous columns, together with bolt- and rod-iron, ironwire, anchors, grapnels, &c., hoops, nails, and all other sorts not included in the foregoing.

2,342,674

12 3 7

2,009,259

10 6 10

2,535,692

9 18 1

2,719,824

10 19 6

2,524,859

9 8 2

2,877,278

7 19 5

2,457,717

6 13 0

2,590,833

5 15 5

3,193,368

6 19 2

9 18 11

Quantity and declared Value of Iron, wrought and unwrought, exported to the United States of America in each year from 1831 to 1844.

Years,

Tons.

Value.

£248,707

1838.

1832.

37,565

74,772

801,198

1833.

54,124

38,603

355,534

1834.

40,625

79,186

626,532

1835.

51,951

58,418

394,854

1836.

79,330

1837.

49,204

489,309 1844.

223,668

696,937

APPENDIX No. 12.

Quantity and declared Value of Iron exported to France in each year from

APPENDIX No. 13.

Estimated quantity of Iron required for the construction and putting into operation each mile of Railway.

Rails, chairs, locomotives, turntables, &c., 50 tons of wrought- and cast-iron, equal, each year, to 61 tons of pig-iron.

N.B. The above estimate has been furnished by an experienced railway engineer to the chairman of a railway company. The quantities are greater than are com monly assigned, but an abatement of 25 per cent. would not disturb the calculation made by me (page 109); and when provision is made for maintaining in repair the railways now open, it would absorb all the iron which will probably be made in the next four years, to construct, at that abatement of 25 per cent., the lines now sanctioned by Parliament.

Third Report on Atmospheric Waves.
By WILLIAM RADCLIFF BIRT.

THE two former Reports which I have had the honour to present to the Association necessarily possessed a fragmentary character. Sir John Herschel, in his Report on Meteorological Reductions (1843), distinctly traced two well-defined atmospheric waves which passed over the British Isles and the west of Europe, one in September 1836, the other in December 1837. These may be regarded as the earliest instances of our detecting and clearly apprehending the character of the atmospheric undulations constantly traversing our oceans and continents, and mark the commencement of that æra in atmospheric research to which Mr. Forbes alluded in his Report on the Recent Progress and Present State of Meteorology, presented to the Association in 1832, when he said, "The great extent of country over which the accidental variations of the barometer take place, is one of their most striking features; and in a future and more advanced state of meteorology we may be able to draw the most interesting and important conclusions from the great atmospheric tidal waves which are thus perpetually traversing oceans and continents."

Sir John Herschel, in the conclusion of the report to which allusion has been made, noticed the larger fluctuations which I had observed in the autumn of 1842, especially the symmetrical wave which occupied thirteen days in November for its complete rise and fall. The curves representing these larger undulations were appended to Sir John Herschel's report; and the Association, under the direction of the Magnetical Committee and the immediate superintendence of Sir John, entrusted me with the further in

vestigation of these waves, especially that of November. The mode of investigation and the partial results arrived at during the period between the sittings of the Association in 1843 and 1844 form the subject of my first report, which, as before stated, must be regarded only as a fragment.

During the further investigation of the wave of November various observations came to hand, which appeared to throw considerable light on the general character of atmospheric undulations. The publication of the Greenwich and Toronto observations afforded an interesting comparison of the passages of certain maxima at these distant stations, and by extending this comparison to Prague and Munich, several interesting features of certain secondary waves during the transit of a supposed normal wave appeared so clearly to be made out, that it was deemed desirable to include the whole of this comparison in the succeeding report, rather than run the risk of its being lost by deferring it until after the examination of the great wave should be completed. Another most interesting result arrived at about this time, was the recurrence of the great wave of November. The return of this interesting phænomenon appeared so strikingly distinct in 1843 and 1844, that to have omitted noticing it in the Report would have greatly contributed to retard the inquiry. It accordingly forms the second section of the Report of 1845. These circumstances, with the further investigation of the great wave of November 1842, give to the second report a more fragmentary character.

Previous to entering on the immediate subject of the present report, it will be desirable to review the steps that have been taken for observing the great symmetrical wave on its return in 1845; and also to notice any other circumstance that may have transpired during the past year at all calculated to throw any light on the subject of our investigations. With regard to the first point, certain instructions were drawn up, which were forwarded to gentlemen interested in meteorological research, and otherwise circulated, in consequence of which a number of interesting and valuable observations were obtained. The results of the examination of these observations, as far as it has yet proceeded, will form the first part of the present report. In the Philosophical Magazine for April in the present year Mr. Brown published a voluminous paper on the oscillations of the barometer, with particular reference to the meteorological phænomena of November 1842, the month in which I first observed the great symmetrical wave. This paper is accompanied by diagrams representing the direction of the wind in England, Scotland and Ireland every day, from the 1st to the 26th inclusive. Upon a very careful perusal of it, I found that the observations, as given in the diagrams, very beautifully illustrated Prof. Dove's theory of parallel currents or alternately disposed beds of oppositely directed winds, and appeared to throw so clear a light on the real character of the atmospheric undulations, that I was induced to enter upon a very careful examination of the barometric observations in connexion with the diagrams of the wind. The result of this examination has been to give the inquiry a completeness which it was before destitute of. It was previously difficult to define the real notion we formed of an atmospheric wave; not so much from the distribution of pressure over a tract of country gradually decreasing on each side a line of maxima, as from the relation of the aerial currents or winds to this distribution of pressure of which we were to a certain extent ignorant. The examination of these observations has exhibited very clearly the distribution of the aërial currents in relation to the distribution of pressure, and enabled us to define the nature of an atmospheric wave both as regards its undulatory and molecular motion. This definition, with the examination of the observations, forms the second part of this report.