Part 34 (1/2)

Newcoine proper, producing the ine as a train of ine, as in Savery's, we noticed the use of surface condensation first, and subsequently that of the jet thrown into the midst of the stea improvements, and co the condenser froe ceased, the several i conducted each in a separate vessel The boiler furnished the steam, the cylinder derived from it mechanical power, and it was finally condensed in a separate vessel, while the pohich had been obtained froh still other parts, to the pumps, or wherever as to be done

Watt, also, took the initiative in another direction He continually increased the efficiency of thethe proportions of its parts and the character of its work it possible to render available many of those ireatly dependent and which are only useful when made by a skillful workman

Watt and his conteher pressures of stea feature noticed in the progress of stea since his time Newcomen used steam of barely more than atmospheric pressure and raised 105,000 pounds of water one foot high with a pound of coal consumed Smeaton raised the pressure somewhat and increased the duty considerably Watt started with a duty double that of Newcomen and raised it to 320,000 foot-pounds per pound of coal, with steaeneral plan as those of Watt, but worked with 40 to 60 pounds of steaing, with the better class of engines, 600,000 foot-pounds per pound of coal The coure up to above 1,000,000

The increase in steam-pressure and in expansion since Watt's tireat iely, of the rapid increase in perfection, and in the wide range of adaptation ofengines and boilers, by increased piston-speed, greater care in obtaining dry stea it dry until thrown out of the cylinder, either by stea, or both coreater attention to the iainst losses by radiation and conduction of heat We use, finally, the co some of the heat usually lost in internal condensation and reevaporation, and precipitation of condensed vapor froh there is a limit, tolerably well defined, in the scale of teained in approaching this lower lie of te temperatures[116]

[116] The fact here referred to is easily seen if it is supposed that an engine is supplied with steam at a temperature of 400 above absolute zero and works it, without waste, down to a teine to the use of steaine, with equally effective provision against losses, between the lie with a lower ives an efficiency of one-half, the second three-fifths, and the third three-fourths, the last giving the highest effect

Hence the attempt made by the French inventor, Du Trembly, about the year 1850, and by other inventors since, to utilize a larger proportion of heat by approaching more closely the lower limit, was in accordance with known scientific principles

We rowth of the steaine thus:

_First_ The process of improvement has been one, primarily, of ”differentiation;”[117] the number of parts has been continually increased; while the work of each part has been si appropriated to each process in the cycle of operations

[117] This terineers, expresses the idea perfectly

_Secondly_ A kind of secondary process of differentiation has, to some extent, followed the completion of the primary one, in which secondary process one operation is conducted partly in one and partly in another portion of the machine This is illustrated by the two cylinders of the coine

_Thirdly_ The direction of improvement has been reater expansion, provision for obtaining dry steaainst loss of heat by conduction or radiation, and, in ines, by surface condensation

The direction which i, and the proper direction, as indicated by an examination of the principles of science, as well as by our review of the steps already taken, would see between the widest attainable limits of tehest possible temperature, must be protected from waste, and must retain, at the moment before exhaust, the least possible aenius, or her steam with safety and without waste, or the reduction of the tee, confers a boon upon ine, the tendency is, and may probably be expected to continue, in the near future at least, toward higher steareater expansion in , a careful use of non-conducting protectors against waste, and the adoption of still higher piston-speeds

In the boiler:through the furnace, and ases The latter will probably be ultiht, in place of the farit by the expenditure of heat in the chimney

In construction we may anticipate the use of better materials, and more careful workmanshi+p, especially in the boiler, and much iement, there is a wide field for improvement, which improvement we may feel assured will rapidly take place, as it has now becoence are ieine, and that they repay, liberally, all of the expense in time andiht of folly to assume that we have reached a limit in any one of theress seems checked by inadequate returns for efforts made, in any case, to advance beyond present practice, it becoineer to detect the cause of such hinderance, and, having found it, to reo, the h stea to prove positive disadvantage to follow advance beyond a certain point A careful revision of results, however, showed that this was true only with engines built, as was then coard of all the principles involved in such a use of steam, and of the precautions necessary to be taken to insure the gain which science taught us should follow The hinderances are ineer to remove them

The last reineer who is atte to advance in the direction in which, as already inti, the ine to adapt it safely and successfully to run at the high piston-speed, and great velocity of rotation which have been already attained and which reatly exceeded in the future As there is no known and definite limit to the economical increase of speed, and as the li set farther back as the builder acquires greater skill and attains greater accuracy of workidity of parts and durability of wearing surfaces, we ress in this direction--a progress which e, whatever es may take

It is evident that this adaptation of the steareat speed of piston is the work now to be done by the engineer The requisites to success are obvious, and may be concisely stated as follows:

1 Extreme accuracy in proportions

2 Perfect accuracy in fitting parts to each other

3 Absolute symmetry of journals

4 A surfaces