Birth Of The Steam Engine.

describe the progress from one improvement to another , illustrating as Ave proceed , a few of the results that have been brought about by its agency . We uoticed , in our last , some antecedents of the steam engine . It happened , singularly enough , that in the very year that old Jonathan Hulls published his proposal to furnish vessels which could by the

agency of steam be conveyed in and ovit of port , Avas born the child whose matured genius was to reduce to practical utility the dreams of the enthusiasts . About the year 1763 , Watts Avas a young man , carrying on the business of a mathematical instrument maker in Glasgow . A model of a steam enginesuch as the steam engine was at that timeAA'as brought

, , to him for repair . In the experiments which it became his duty to make , the shreAvd artificer soon observed that Avhich aroused his attention and directed him more particularly to the princi ples of its construction and the purposes of its use . Great men have been led to their discoveries by common incidents . ISTeAvton ' s falling apple was the key which opened

up to the eye of genius the laws of the upper universe . Galileo ' s pendulum led him to discoA'er tlie truths in connexion with earth's density , and to weigh it , so to speak , in his hand . The simple device by which the needle

manufacturer of our time is enabled to arrange his wares for the market , in a former time suggested the loadstone aud the mariner ' s compass . To natural but insignificant changes may be traced the discovery of the means by which mankind might be preserved and improved . So it was Avith Watt . He observed that the quantity of steam consumed at each stroke of the piston was many times more than the cylinder

could contain . This struck him as an anomaly , aud he at once meditated a remedy . The immense quantity of water required to effect condensation , also created surprise , and led him to make certain experiments by which some ofthe most important phenomena connected Avith latent heat ancl evaporation AA ere evolved . The student hastens to a professor

in the GlasgoAv University AA'ho had some theory on the subject , and from whom he received encouragement to prosecute his inquiries . These kind words increased his energy , aud he Ai'orked AA'ith a more exalted feeling of his business . Ho had , perhaps , no visions of tho great things he AVUS destined to achieve . He did not foresee the miht }* agency that

g was to grow up under his hand , but ho Averted on patiently , confidently , and hopefully , inspired by those noble princi ples which it is the province of our glorious Craft to inspire , and of which Craffc Watt became an illustrious member .

When the steam engine AVUS applied only to the purpose of pumping water out of coal , mines , as AA * O have already explained , ifc ivas simply necessary to raise tlie pump rod , tho Avei ght of AA'hich was sufficient to cause ifc to descend , and in the interval give tho steam machine a rest-, sufficient to prepare it for the next exertion . Watt had no such

consideration for the repose of the iron monster . Saving of time is a saving of money , ancl as tlie creature ate more coals and drank more water than AVUS necessary for the sustenance of active and energetic health , the mechanician determined to supply it with a . kind of second stomach , which AVUS to be found iu a separate condensing vessel . By this means

condensation became immediate Avithout suffering any diminution from obviating causes , such as had previously existed . The functions of the creature were now performed without obstruction . It required but another improvement to give a neAV motion , ancl the quiet mathematical instrument maker was not long in finding out the moans for its

accomplishment . 'The first experiments were failures , but each failure brought its li ght with it , and so from experiment to experiment a sum of expedients and means to ends were discovered , ivhich intelligently combined ancl ordered , gave to the labourer ultimate success . We hear now more frequently of cranks , throttle valves , governors , fly wheels , connecting rods . This was called a double acting condensing steam eng - , and is in reality the first parent of the modern

locomotive . This engine performed every function after having been supplied Avith its alloAvance of coals and water . It effected an enormous saving both of time and material . But all this was not enough to give the inventor an interest in his discovery . At the end of tiventy years from the date of his first experiments , Watt and his partner found that the

manufacture of these engines had not been a source of profit to them , but had entailed upon them a loss of capital amounting to about £ 50 , 000 ; an application had to be made to parliament to extend the patent , which the legislature was with difficulty induced to grant until the year 1800 . Although there have been many improvements since the time

of Watt , there has been no change or alteration of the principles upon which he worked . Next in order came the expansion steam engine , the rotatory steam engine , the marine engines , which as they UOAV form the bulwarks of our navy and our commerce , we may pause a feAV moments to describe .

Brethren who may be travelling on the silvery bosom of sAveet smelling Thames to a Greenwich dinner this fine weather , will generally find the skyli ghts of the engine room open , and if they are disposed to gratify their curiosity , or gather information upon this subject , they will have abundant opportunity . Looking clown into this marine dungeonif

, they are not deterred by the presence of an oleaginous vapour that is by no means agreeable , they will see tAvo enormous wedges of metal rising and falling alternately , and as each one falls or rises there is a rumble coincident ivith a

perceptible effort the more apparent if the river be smooth . For the benefit ¦ of such as have not paid attention to the skeleton of this steam marine horse which pushes them along , we give a short description , premising that Ave do not intend to be either as luminous or as lucid as Professor OAVCII is said

to be upon the organization of the megatherium , but briefer by a long ivay , which compensation AVO offer as amply sufficing for the use of hard words and harder names . A shaft then , we will say , is carried across the vessel , being continued on either side beyond the timbers . At the extremities of this shaft , on the outside of the vessel , are attached a pair of

wheels constructed like undershot water Avheels , having fixed upon their rims a number of flat boards , called paddle boards . As the Avheels revolve , these paddle boards strike the water , driA'ing it in a direction contrary to that in which it is intended the vessel shall be propelled . The moving force imparted to the water , thus driven backwards by reaction

on the vessel , propels it . ISTOAV , on the shaft in the interior are fixed tAvo cranks—the wedges of metal spoken of—placed at right angles to each other , so that whenever one of them , is thrown into the hig hest or lowest position , the other is horizontal . These cranks are Avorked by strong iron rods , called connecting rods , which may be seen attached to them , and which are themselves either driven directly by the

p istons of tho steam engine , or aro worked by those pistons , in this particular fche medium of working being precisely the same as in the ordinary land engines . The tAvo cranks being placed at rig ht angles , it folloAvs that when one piston is at tho top or bottom of its stroke , and the crank is driven by ifc into the hig hest or lowest position , the other will be at it ivill be

tho middle of its stroke , and the crank driven , by in a horizontal position . One of the pistons is therefore ahvays in a position to produce the most advantageous effect on the crank at the moment that the other piston loses its power , and in the same manner it may be seen that while the power of the one piston is augmented from zero to its

highest effect , the power of the other is decreasing from its greatest effect fco zero , thus tho combined action of the two p istons is nearlj uniform in its efficiency . If one engine only were used , the motion of the Avheels would be unequal , beiii" - most rap id Avhen the piston is at the middle of the stroke , ancl slowest at the extremities . Watt had scarcely fulfilled his mission , when another