TRANSACTIONS OF THE SECTIONS. 151 



whicli appeared in detail in the Philosopliical Trausactious ; but the importance 

 of the results contained in them makes it necessary to refer to them now. Those 

 results constitute the first direct determination of the density of steam ; and besides 

 their practical value, they furnish a most remarkable confirmation of the djiiamical 

 theoiy of heat, because they agree very nearly with the densities of steam which 

 had been deduced from the laws of its pressure and latent heat four or five years 

 before, by calculation according- to the principles of thermodynamics. 4. Steam- 

 Boiler Explosions, 1863, by the Astronomer Koyal, showing the great explosive 

 energy possessed by a mass of liquid water at a high temperature. 



It has been established beyond the possibility of doubt, according to the second 

 law of thermodynamics, that the utmost quantity of work which can be got by the 

 expenditure of a given quantity of heat depends solely on the limits of temperatm-e 

 between which the engine works, and is independent of the nature of the fluid to 

 which the heat is applied, such as water, ether, air, ammonia, &c. The means 

 of improving the economy of heat in thermodynamic engines are of three 

 kinds : first, working expansively, so as to obtain from the lieat applied to the 

 fluid all the work that is possible between given limits of temperature,-— this has 

 probably been already earned to the utmost extent practicable ; secondly, increasing 

 the range between those limits of temperature, — to this there are bouud.s set in 

 practice by the conditions of durability and safety ; and thirdly, dimiuishiug the 

 quantity of heat which goes to waste from the furnace. The last is probalily the 

 means which at present holds out the greatest probability of improvement upon the 

 economy of the most economical steam-engines of the present time. It is probable 

 that the use of rock-oil as fuel may contribute towards that result ; and something 

 may perhaps be hoped from the direct use of the products of combustion to drive 

 the engine. 5. Gun-cotton, 1863-05. In these reports by a Committee, it is 

 shown how gun-cotton is adapted to various pui-poses by suitable mechanical pre- 

 paration. 



Hydraulic Unf/uiceriitf/.—l. On the Water-Supply of Towns, 1855, by Mr. Bate- 

 man. A report (Df great interest, on a subject worthy of the continued attention of 

 the Association. 2. On Eainfall, 1864-66. A series of reports by a Committee, 

 based chiefly on observations collected by Mr. SjTUons. These will probably be 

 continued annually. 3. On Weii--Board Gauges, 1856, 1858, 1860-61, by Prof. 

 James Thomson. These reports contain the resiflts of experiments on the gauging 

 of the flow of water in sti'eams by means of " notch-boards," showing how accuracy 

 is to be ensured iu such gauging-; and, in particular, the properties and advantages 

 of triangular or ^^-shaped notches. 4. Tides on the Trent and Humber, 1864, 

 by INIr. Oldham. 



ShipbuiUling and Steam Navigation. — 1. The Strength of Materials in Iron Ship- 

 building, and the Resistance of Arniom'-plated Ships to Penetration, have been 

 referred to imder another head. 2. Tonnage of Ships, 1850-57, bv a Committee. 

 3. Steam Na^dgation at the Port of Hull, 1853, 1859, 1861, by Mr. Oldham. 4. Ii-on 

 Shipbuilding on the Tyue, Wear, and Tees, 1863, by Mr. Palmer. The three pre- 

 ceding subjects partake of a statistical as well as a mechanical character. 5. Life- 

 Boats, 1854, by General Chesney. 6. Statistics of Life-Boats and Fishing-Boats, 

 1857, by Mr. Henderson. 7. River Steamers, 1858, by Mr. Henderson. 8. Mer- 

 cantile Steam Transport Economy, 1856-57, 1859, 1801, by Mr. Atherton. 

 9. Shipping Statistics, 1858, by Admiral Moorsom. 10. Resistance of "Water 

 to Floating and Immersed Bodies, 1865-66. Report of Experiments, by a Com- 

 mittee. 11. Steamship Performance, 1857-63: — A series of reports of data col- 

 lected from various quarters by a Committee, presided over at first by the late 

 Admiral Moorsom, and aftei-wards by His Grace the Duke of Sutherland. Re- 

 ferring more especially to this last-mentioned series of reports (and also to the 

 reports of the experiments of Mr. Scott RusseU on Waves, published previously to 

 the period to which this summary is limited), it may be held that the reports and 

 archives of the British Association contain, perhaps, the greatest mass of data of 

 experiment and practice ever brought together for the pui-pose of improving the 

 science of the designing and propiilsion of vessels. The bulk of that mass of in- 

 formation is so great that it was resolved last year to appoint a committee for the 

 purpose of condensing it ; and a report by that committee will be laid before this 



