1848."! 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



249 



corresponding with the height the rod is lifted at each movement. 

 Each bucket to be raised by these rods is furnished with two spring- 

 hooks, which take into the notches on the rods and suspend them 

 while ascending; tlie bucket being suspended from the lowest 

 notcli, is elevated bv the first movement, till the spring-hook slips 

 into the second notch on the other rod. The rod liy which it has 

 been previously lifted, descends, thereby transferring the whole 

 weight to the other rod, which immediately raises it another step, 

 the" changes being performed alternately in this way until the 

 bucket reaches the top. 



STEAM-ENGINES. 



Chakles William Siemens, of Manchester, for '^ Improvements 

 in engines to be worked bi/ steam and other /k?V/s."— Granted Decem- 

 ber 22, 184.7; Enrolled June 22, 1848. 



The chief object of this invention is the saving of fuel by a 

 means proposed for regenerating the steam and for condensing it 

 by successive exposures to water of different temperatures. There 

 is no regular boiler employed, but the steam is generated in the 

 first instance in a small flat chamber, placed close to the cylinder; 

 the direct action of the fire being against a cast-iron chamber con- 

 taining the bottom of the cylinder, and having considerable space 

 between the two, which is filled with lead. The flues are continued 

 twice round the cylinder, and then carried under the steam-gene- 

 rating chamber. The cylinder is fitted with a Jacket, through 

 which the steam has access to both sides of the piston, the area of 

 the upper side of which being diminished one-half by a trunk 

 which works through a stuflfing-bo.\ in the top, and admits of the 

 connecting-rod passing down to the piston, the difference of the 

 area causing the piston to ascend. The steam having been thus 

 admitted to the cylinder, is suffered to escape by a series of double- 

 beat valves, which are lifted by a series of cams on the main shaft ; 

 the steam is thus admitted successively into eight different regene- 

 rating-chambers, which are placed immediately under the generator. 

 The steam, as admitted to the upper chamber, will be of tlie greatest 

 pressure, and the valve is suffered to remain open a very short 

 time, the next in succession opening immediately, the duration of 

 which will be somewhat longer, which goes on increasing, the 

 pressure of the steam being also gradually reduced ; the ninth 

 valve opens to the atmosphere or to the condenser, and remains 

 open till the engine is past the centre. These several chambers 

 are each fitted with shallow horizontal trays, into which water 

 escapes from the generator above, passing from one to the other. 

 The heat thus communicated to tliese chambers regenerates the 

 steam, which is again admitted to the same cylinder, or to another 

 cylinder, should it be a double-cylinder engine, by tlie same set of 

 valve.s. which are opened by another set of cams on the opposite 

 side of the shaft, in the inverse order to that before explained, the 

 lowest pressure being allowed to act first. The heat communicated 

 by the fire to the cylinder also assists in the regeneration of the 

 -Steam. The next part of the invention relates to the condensation 

 of steam in ordinary condensing-engines. The condenser is sub- 

 divided by horizontal partitions, into four or five separate compart- 

 ments, the steam being admitted by a cock having a hollow plug, 

 which is opened to the cylinders. This plug opening to the separate 

 compartments of the condenser in succession, beginning at the 

 lowest, the injection water is admitted to the uppermost, where it 

 completes the condensation of the steam, and from which the air- 

 pump exhausts a portion of the injection ; and the condensed water 

 instead of being carried off by tiie air-pump, is received between 

 two pistons working in a barrel between the upper and second 

 chamber, by reason of the upper piston being above the top of the 

 cylinder or barrel. This water is by the down stroke of the air- 

 pump admitted to the (diamber immediately below the injection 

 chamber, and in which a portion of the steam is suffered to escape. 

 Each of the partitions is fitted with similar apparatus for transmit- 

 ting the condensed water from one chamber to the other, till it 

 reaches the lowest, where the steam is first admitted. A portion 

 of the steam on entering that chamber will be condensed by the 

 water, and after having passed through all the separate chambers, 

 and having the heat derived from several successive charges of 

 steam from the cylinder, it will have attained a great heat, and 

 may be introduced to the boiler. The quantity of water required 

 for injection will thus be materially reduced, and may render it 

 applicable to locomotives for condensing the atmosphere of the 

 steam which remains in the cylinder after its high-pressure effect 

 is spent through the blast-pipe in the chimney. The last part of 

 the invention relates to an improvement in the ohronometric 

 governor, patented by Mr. Siemens, in December, 1846. The 



improvement consists in the adaptation of an expanding fly-wheel 

 to the governor, instead of the pendulum-ball with which it was 

 originally constructed. This fly-wheel is formed in four segments, 

 and by centrifugal action they are caused to expand or recede from 

 the centre. When any excess of the centrifugal force takes place, 

 by reason of the increased velocity, bell-crank levers are actuated 

 by the segments, so as to force a conical friction-break against a 

 cone fixed to the frame-work. The friction cau.sed by this break 

 tends to retard the velocity of the shaft and segments, and the 

 power which is exerted to drive the shaft being constant and 

 independent of the velocity of the prime mover, limits the velocity 

 of the expanding-wheel, causing nearly a uniformity of motion, if 

 sufficient power be at all times transmitted to the shaft. 



REPLY TO THE REVIEW OF DR. GREGORY'S 

 " MATHEMATICS FOR PRACTICAL MEN." 



Sir — In the criticism upon the new edition of Dr. Gregory's 

 " Mathematics for Practical Men," which appeared in the last 

 number of your Journal, the writer has in such positive terms de- 

 nounced as incorrect certain portions of that work, involving 

 principles not however peculiar to itself, but which have origi- 

 nated with, or been demonstrated by, all the principal mathematical 

 writers, that I think myself called upon to otter the following 

 remarks, to prevent your readers being misled upon the subject. 



Your reviewer commences his criticism by expressing his sur- 

 prise at my using the words cycloid and trochoid synonymously; I 

 am not, however, the only person who has done so, for 



Dr. Huttoii says: " Trochuid is the same curve as what is more usually 

 called the cyiluid."' 



Professor Barlow says : " Trochoid Is the same as cycloid, that term being 

 derived in a similar manner from x^X^ s, a circle. It Is, however, hy some 

 authors, used to denote exclusively the piolate cycloid. '"- 



Your reviewer then proceeds to find fault with my definition of 

 an epicycloid, which is as follows: — 



"If the generating circle, iiisiearl of rolling along 1 

 a straight line, is made to roll upon the circumference 

 of another circle, the curve riescriheil hy any point in 

 its circumference is called an epicycloid." p. 179. 



equal to the fixed 

 circle, and rolls on 

 the exterior of it." 



Your reviewer 



says : " It is not 



called aneptcycloidp 



^ ,, .,,.,■ , t , , . 1- 1 except when the 



Dr. Hutton says : liut ,f, instead of the nght Ime, Y J,^,- ,i^^,, ;, 



the circle roll ainiig the circumference of another „„.,„| ,„,[,„ «... 



circle, either equal to the former or not, then the 



curve descrilied hy aiiy'pnint in its circumference is 



v\hat is called the epicyclrAd."^ 



Now, Professor Barlow ■* gives the properties of epicycloids 

 when the generating and quiescent circles are not commensurable, 

 which they always would be if equal and Dr. Young,'' in an 

 " Essay on Cycloids" (the attentive perusal of which I would 

 recommend to your reviewer), speaks of epicycloids in which, 

 while one circle remains constant, the other becomes either 

 infinite or evanescent. !f, then, your reviewer is riiiht, it follows 

 that Dr. Hutton, Professor Barlow, Dr. Young, aiul many others 

 (whom I have not space to quote), are wrong. 



He then goes on to say, that I have aggravated the mistake 

 "by representing the rolling curve as much larger than the fixed 

 curve," whereas it is really much smaller in both my figures (157 

 and 158); from which it is very evident that he has mistaken 

 the fixed for the rolling circle. 



Your reviewer next finds fault with one of my definitions, as 

 being "clumsy and incomplete, at the least;" and asks, _" What 

 will our mathematical readers say of such a definition.?" Now, 

 one of our most justly-esteemed mechanical writer.s. Professor 

 Moseley, has given a definition so precisely synonymous, that I 

 transcribe both his and my own for the purpose of comparison: — 



Professor MoscUy's Definition. Definition Criticised. 



" When more luiies lliaii one are "Whtntlie forces that act upon 



applieil to a hody, and their respec- a borly, deitroy or annihilate each 



other's operation, so that the body 

 remains quiesctnt, tliry are said to 

 be ill ei/uilihrium, and are then 

 called pressures." p. 187. 



tive tendencies to communicate mo- 

 tiiin to it counteract one another, so 

 that the body remains at rest, these 

 forces are saul to he in equititiriumj 

 and are then called pressures."'^ 



Your reviewer objects to the sense in which I here use the word 



« i'liil. iiiiil fllii.b liiLiiui.ary, vol. J p. .'>4l- 



2 Neiv Jlalh. and Phil. liRiiiinary. An. •TrochoiJ." 



;» iM.ll. and iUatli. Dittiintary. vol. 1, (j. 475. 



" Nov Bialh. and Phil. Uimoiiaiy,— An. ■' Epicyiljid." 



s A course ot Lpcluieson Nal. Pint., vol. 2, p. 55K. 



" Meihauk-at Principles of i-lugineeriug and Arcb., p. 1. 



33 



