ON THE DEVELOPMENTS OF MECHANICAL ENGINEERING. 495 



frained from occupyiug tlie time of the Section by a retrospect, and 

 devoted himself, in that lucid and clear address with which he favoured 

 us, to the consideration of certain scientific matters connected with en- 

 gineering, and to the foreshadowing of the directions in which he believes 

 it possible that further improvements may be sought for. But I feel it is 

 desirable that some one should give to this Section a record, even although 

 it must be but a brief and an imperfect one, of certain of the impi-ove- 

 meuts that have been made, and of some of the progi-ess that has taken 

 place, during the last fifty years, in the practical application of mechanical 

 science, with which science and its applications our Section is par- 

 ticularly connected. I regret to say that, in common with most of the 

 gentlemen who sat on this platform yesterday — who I think were, 

 without exception, past Presidents of the Section — I am old enouo-h to 

 give this record from personal experience. Fifty years ago I had not 

 the honour of being a member, nor should I, it is true, have been eligible 

 for membership of the Association; for I was at that time vigorously 

 making models of steam-engines, to the great annoyance of the house- 

 hold in which I lived, and was looking forward to the day when I should 

 be old enough to be apprenticed to an engineer. 



Without further preface, I will briefly allude to some of the prin- 

 cipal developments of a few of the branches cf engineering. I am well 

 aware that many branches must necessarily be left unnoticed ; but I trust 

 that the omissions I may make will be remedied by those present who 

 may speak upon the subject after me. 



I will begin by alluding to the Steam Engine employed for manufac- 

 turing furposes. In 1831 the steam-engine for these purposes was 

 commonly the condensing beam-engine, and was sujiplied with steam 

 from boilers known, from their shape, as waggon-boilers. This shape 

 appears to have been chosen rather for the convenience of the sweeps, 

 who periodically went through the flues to remove the soot consequent 

 on the imperfect combustion, than for the purpose of withstanding the 

 internal pressure of steam. The necessary consequence was, that the 

 manufacturing engines of those days were compelled to work with steam 

 of from only 3|- lbs. to 5 lbs. per square inch of pressure above atmo- 

 sphere. The piston-speed rarely exceeded 2£0 feet per minute, and as 

 a result of the feeble pressure and of the low rate of speed, very large 

 cylinders indeed were needed relatively to the power obtained. The 

 consumption of fuel was heavy, being commonly from 7 lbs to 10 lbs. 

 per gross indicated horse-power per hour. The governing of the 

 engine was done by pendulum-governors, revolving slowly, and not 

 calculated to exert any greater efi'ort than that of raising the balls at 

 the end of the pendulum-arms, thus being, as will readily be seen, 

 very inefficient regulators. The connection of the parts of the engine 

 between themselves was derived from the foundation upon which the 

 engine wa;S supported. Incident to the low piston-speed was slowness 

 of revolution, rendering necessary heavy fly-wheels to obtain even an 

 approach to practical uniformity of rotation, and frequently rendering 

 necessary also heavy trains of toothed gearing to bring up the speed 

 from that of the revolution of the engine to that of the machinery it 

 was intended to drive. 



In 1881 the boilers are almost invariably cylindrical, and are very com- 

 monly fired internally, either by one flue or by two ; and we owe it to the 

 late Sir William Fairbairn, President of the British Association in 1861, 



