TRANSACTIONS OF THE SECTIONS. 235 



have already been obtained, but they are not yet sufficiently advanced to be made 

 public. The following numbers have been, however, approximately reduced from the 

 theoretical formula above, and the experimental results may illustrate the use of this 

 method of research. The most convenient way of expressing tbc density of steam, is 

 by stating the number of volumes into which the water of which it is composed has 

 expanded. Thus one cubic inch of water expands into about 1G70 cubic inches of 

 steam at 212° Fahr., into 882 cubic inches at 251°, and into 400 cubic inches at 304°, 

 and so on; in this way the following numbers have been computed : — 



Temperature Pressure in Volume by 



Fahr. ins. of Mercury. Experiment. 



155-33 8-62 5326 



159-36 9-45 4914 



174-92 1362 3433 



188-30 18-36 2620 



242-90 53-61 941 



244-82 55-52 906 



255-50 66-84 758 



267*21 81-53 634 



279-42 99-60 514 



287-25 112-78 457 



292-53 122-25 432 



These determinations at pressures varying from ten to fifty lbs. above the atmo- 

 sphere, uniformly show a decided deviation from the law for perfect gases, and in 

 the direction anticipated by Professor Thomson, the density being uniformly greater 

 than that indicated by the gaseous formula. We hope, by the time of the next meet- 

 ing of the Association, to be enabled to lay before the Section a series of results 

 which will fully determine the value of superheated steam, and its density and volume 

 as compared with water at all pressures, varying from that of the atmosphere to 500 

 lbs. on the square inch. 



Ait Experimental Illustration of the Gyroscope. By Alexander Gerard. 



Description of the Granite Quarries of Aberdeen and Kincardineshire. 



By Alexander Gibb. 



The author gives an account of the commencement, progress and present condition 

 of the granite quarries of Aberdeenshire and Kincardineshire, particularly of those in 

 the immediate neighbourhood of Aberdeen, giving an account of the chief uses to 

 which the stone has been applied. He then proceeds to show the most economic 

 methods of working, the drawing steam power required, the tools and number of 

 workmen employed, with the improved methods of dressing the stone, and the various 

 ornamental as well as useful purposes to which the stone has been applied. 



On Gas Carriages for lighting Railway Carriages with Coal-gas instead 



of Oil. By G. Hart. 



The author proposes to have a reservoir of gas or a carriage constructed to carry 

 gas and to accompany each train. He then proceeds to show how it may be con- 

 veyed to each carriage and burned in the ordinary way. Supposing a train to 

 consist of two first, four second, and four third-class carriages, and fitted up with 

 twenty-two Argand burners (twelve holes), the quantity of gas required for a journey 

 of twelve hours would be 800 feet. 



On Indian River Steamers and Tow Boats. By Andrew Henderson. 



The author gave an account of their improved construction for light draft, capa- 

 bility for cargo, and fittings conducive to management in shallow rapid rivers, &c, 

 and of the practical value of the dynamometer in showing the resistance of vessels 

 in tow, at different speeds and loads, with the result of test-trials made in England. 



