732 KEPORT— 1889. 



thoroughly practical as well as scientific men ; they determined their constants by 

 reference to a large number of successful cases ; and I sincerely hope that the 

 •question will be pursued by the marine-engine builders on the West Coast, and by 

 the constructors of land engines. As engineer to the Royal Agricultural Society 

 I have frequently had to define the power of engines entered for competition for 

 the Society's prizes, and I have experienced the greatest difficulty in laying down 

 rules for the guidance of intending competitors, being fearful, on the one hand, of 

 restricting originality, and, on the other, of admitting engines of greatly varying 

 powers. 



I have expressed an opinion that the numerous engineering societies which 

 exist at this day have it in then- power to promote the advancement of mechanical 

 science in a notable manner by appointing research committees, or by aiding indi- 

 vidual investigations from their abundant means. The North-East Coast Institution 

 of Engineers and Shipbuilders has done good service in their endeavours to 

 establish a practical measure of the power of marine engines, while the Institution 

 of Mechanical Engineers has, for the last ten years, been steadily promoting 

 researches of an eminently practical nature. Their expenditure has reached the hand- 

 some sum of 1,700/., and their proceedings have been enriched with reports on the 

 ' Hardening, Tempering, and Annealing of Steel,' on the ' Form of Riveted 

 Joints,' on ' Friction at High Velocities,' on ' Marine Engine Trials,' and on the 

 ' Value of the Steam Jacket.' The names of those who are acting on these Com- 

 mittees are a guarantee that the investigations conducted by them will rank among 

 the classical works of the profession, and will abundantly justify the liberal 

 expenditure which has been incurred. 



It is impossible to conclude the address which I have had the honour of 

 delivering without an allusion to the most important structure which engineering 

 skill and enterprise has ever attempted. The Forth Bridge is rapidly approaching 

 completion, and on Saturday, September 14, Mr. Baker is to deliver a lecture, in 

 which he will, no doubt, tell us when the great work is likely to be completed. I 

 think that the members of this Section belong sufficiently to the ' working classes ' 

 to have a claim to admission to the lecture, and to hear from the lips of the creator 

 of the bridge the story of its inception, of its progress, and his hopes as to its 

 completion. 



The following Papers were read : — 



1. Experiments ujpon the Transmission of Po2ver ly Compressed Air (Popp's 

 System). By Professor A. B. W. Kennedy, F.B.8., M.Inst.O.E. — 

 See Reports, p. 448. 



2. Water-gas in the United States. By Alex. C. Humphreys, M.E. 



Water-gas is generally obtained by the decomposition of steam which has been 

 brought into contact with incandescent carbon. 



The first reaction that occurs is the formation of carbonic acid and the liberation 

 of hydrogen. The carbonic acid is brought into contact with an additional quan- 

 tity of incandescent carbon, from which it takes up an equivalent and becomes 

 carbonic oxide, so that there results, theoretically, a mixture of hydrogen and 

 carbonic oxide in equal volumes. These gases have no light-giving properties, so 

 that if they are to be used for illuminating purposes, they have either to be mixed 

 with some hydrocarbon in the gaseous form, or they must be employed to raise to 

 a white heat some solid substance, such as lime, magnesia, salts of zirconium, 

 lanthanum, or platinum, &c. 



There are two ways of effecting the decomposition of steam : one is intermittent, 

 the other continuous. In the first a furnace of tlie cupola pattern is used, the fuel 

 is raised to the desired temperature bj' a blast of air, which is shut off as soon as 

 this temperature is attained and steam is turned on, the blowing up and the injec- 

 tion of steam succeeding one another intermittently. In the continuous process the 

 carbon is either placed in retorts heated externally and steam passed through 



