miles per hour, an unrecorded speed for ships of any size, close hauled, but surprising for a vessel of 45 tons, and in a very rough sea. It was, in fact, remarked on board, that, as the wind freshened, her pace increased without limit. This agrees with the fact stated by Capt. Fishbourne of the Flambeau steamer, on wave lines, that she had a speed greatest in the worst weather, as compared with her rival. It is perhaps possible to improve sailing vessels greatly, as compared with steamers. When so improved, they might be used where sailing vessels nearly compete with steamers at present. This may be further helped by the diminution of insurance and of the present unnecessary waste of human life. Mr. Bodmer communicated the result of experiments on long and short stroked steam-engines. Mr. Clarke exhibited the model of a new atmospheric tube, in which the sides are elastic enough to close the slit and form a self-acting valve. Dr. Bevan exhibited his mode of applying atmospheric air to propulsion. Mr. Eyton exhibited the model of a compact form of vertical steam-engine, which possessed the advantage of a long connecting-rod. The plan was not quite original, but he had applied it with advantage. On Vulcanized Caoutchouc. By W. BROCKEDON, F.R.S. Mr. Brockedon stated that the discovery in this country was due to Mr. Hancock of the firm of C. Macintosh and Co., Manchester, and that he made it whilst experimenting to fuse caoutchouc and sulphur together. He found that though the sulphur was at 300°, the rubber, which alone would have melted at about 220° and absorbed the sulphur, was thus protected from melting. A chemical union of a certain portion of the sulphur with the caoutchouc took place; and it was found that this process might be carried far enough to carbonize the caoutchouc to the condition of horn, but never to melt it. Mr. Hancock then united sulphur mechanically with rubber; and also dissolved sulphur in the solvents of caoutchouc; and heating these materials so prepared to the necessary degree, found that the change was effected called vulcanized. The new properties which rubber thus acquires are most important in the hands of mechanical engineers, from the increased and permanent elasticity of the vulcanized rubber; it is being brought into extensive application and use for railways, lying between the rail or the chair and the sleeper; for the drag and buffer springs and side springs of railway carriages, waggons and trucks; for washers for steam, gas, and water-pipes, being permanently elastic at low temperatures as well as at very high; even for steam pipes at 50 and 60 lbs. to the inch, they have formed a perfect joint. A Nasmyth steam-hammer of 5 tons weight has fallen 18 inches on a piece an inch thick and 2 inches square without any injury to the form of the rubber. A cannon-ball resting on a piece of vulcanized rubber 1 inch thick has been crushed and broken without leaving, except upon close examination, any trace of its effects on the rubber, when a hole like a leech-bite might be found which had closed after the blow. The layer of corrugated rubber, which had been placed between the rail and the sleeper, after two years' service on the Great Western Line, betrayed no trace of injury or effect of pressure. Upon this new material the solvents of common rubber have no longer the action of solvents; the rubber slowly absorbs them but is not dissolved by them, and when the essential oils are evaporated the vulcanized rubber regains all its strength and elasticity. Its elasticity is permanent and invariable; no cold of our climate has any power to harden it, or the heat of any climate to injure it. These are properties which cannot fail of bringing it extensively into use in the mechanical arts. 1846. Addenda to Mr. Birt's Report on Atmospheric Waves. The following table exhibits the distribution of pressure on the transit of the crest of the great wave, Nov. 18, 1842, with especial reference to the wave, crest No. 4, including St. Petersburgh as a station. A the highest reading at these stations on this day. Altitude of anterior slope. St. Petersburgh to London •68 (A very oblique section.) Altitude of posterior slope. Cork to London 35 (The posterior trough was doubtless some distance north-west of Great Britain and Ireland. November 22. Trough between waves 7 and 9.-The trough now transits St. Petersburgh, crest No. 9 now transits Christiania. We have already noticed that crests 7 and 11 were small waves; abstracting them, we have this succession of large waves thus, Nos. 1, 3, 5, 9. When crest No. 1 traversed England on the 1st, its anterior trough extended beyond St. Petersburgh; when crest No. 3 traversed England on the 10th, its anterior trough also extended beyond St. Petersburgh; when crest No. 5 passed the Orkneys on the 15th, its anterior trough passed St. Petersburgh; and when crest No. 9 passes Christiania (this day), its anterior trough passes St. Petersburgh. These facts clearly show the gradual contraction of the waves or oppositely directed beds of parallel currents. General Conclusion. It will be readily apparent from the collation of Mr. Brown's with the St. Petersburgh observations, that the results arrived at in the preceding discussion have been fully confirmed, and there appears to be but little doubt that the waves as determined in the first instance by a discussion of observations from the stations announced in my first report (Report, 1844, page 267), and further identified and illustrated by the observations collected by Mr. Brown, as well as those which have been brought to light by means of Mr. Brown's observations, and confirmed and illustrated by the St. Petersburgh observations, had a real existence; an individuality has been attributed to certain arrangements of aërial currents and distribution of pressure in connexion with such currents, the aggregate phænomena forming an atmospheric wave. Of the waves thus brought to light, two occupy very prominent positions; they stand out as it were from the others; the individuality of each is very striking, and the velocities with which they traversed the area isolate them from their predecessors and exhibit them not as gregarious, but solitary waves. These waves are B° and crest No. 4, the first occurring just previous to the setting-in of the great wave, and the last forming its crown. The wave, crest No. 4, appears from its elevated position on the symmetrical or normal wave, admirably adapted to crown our investigations with success, especially in so far as its amplitude, velocity and path are concerned, we are now, I apprehend, in possession of materials to determine with a considerable approximation to accuracy, these elements. Its longitudinal direction appears to have been very extensive. This element would receive considerable elucidation by means of observations from the south of France, Spain, Portugal and the north of Africa. It is highly probable that this wave in the direction of its length stretched from the extreme south to the very north of Europe. NOTICES AND ABSTRACTS OF COMMUNICATIONS TO THE BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE, AT THE SOUTHAMPTON MEETING, SEPTEMBER 1846. ADVERTISEMENT. THE EDITORS of the following Notices consider themselves responsible only for the fidelity with which the views of the Authors are abstracted. CONTENTS. NOTICES AND ABSTRACTS OF MISCELLANEOUS MATHEMATICS AND PHYSICS. Professor YOUNG on the Principle of Continuity in reference to certain Results of Analysis ..... ............ Professor OERSTED on the Deviation of Falling Bodies from the Perpendicular Professor POWELL on certain Cases of Elliptic Polarization of Light by Reflexion Page 1 2 on the Bands formed by partial Interception of the Pris matic Spectrum 4 on attempts to explain the apparent projection of a Star on 5 5 the Moon Mr. DALE on Elliptic Polarization Sir DAVID BREWSTER'S Notice of a New Property of Light exhibited in the 7 8 Mr. HENRY LAWSON on an easy Method of contracting the Aperture of a large Telescope ... 9 9 on the Arrangement of a Solar Eye-piece ........... Mr. F. RONALDS on the Meteorological Observations at Kew, with an Account 10 11 Dr. BANKS on a New Anemometer......... 12 Capt. W. W. CHILDERS's Meteorological Observations 13 Rev. T. RANKIN'S Notices of a Halo, Paraselene and Aurora Boreales....... 15 15 16 Mr. G. DOLLOND'S Account of an Atmospheric Recorder........... 17 Mr. C. BROOKE on the Construction of a Self-registering Barometer, Thermometer, and Psychrometer ..... 17 Mr. J. F. MILLER'S Table of the Fall of Rain in the Lake Districts of Cumberland and Westmoreland, &c. in the Year 1845 18 21 24 1846.............. Readings of Mountain Gauges, June, July and August Lt. Colonel SYKES on the Fall of Rain on the Coast of Travancore and Table Mr. E. J. DENT on a New Portable Azimuth Compass...... |