THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



46 



References Pipes, C, witli the necessary 



valves attached to the blowing cylinders, con- 

 vey the air to the steam generator, wliosc outer 

 case, a, a, is four feet diameter, and twelve 

 feet high, and the inner case, or furnace, B, is 

 three and a lialf feet diameter, and nine feet 

 high. Smoke and feed-pipe, D, is constructed 

 with two slides, e, e, which closes the pipe per- 

 fectly tight when thrust into it— their uses will 

 hereafter be explained ; /is a cap-valve in the 

 steam chamber, placed over a short pipe or 

 nozzle on the upper head of the furnace, and 

 fitted to its seat perfectly tight, with a rod ex- 

 tending through the upper head of the outer 

 case; (/ is the ash-pit below the grate; h, an 

 opening into the ash pit, with a slide to close it 

 tight, when necessary. 



In order to put the engine in operation, and 

 successfully use all the advantages of this gene- 

 rator over any other, it will bo necessary to set 

 open the feed and smoke-pipe D, and the pipe 

 h ; introduce fuel down the feed-pipe, in suffi- 

 cient quantity, and ignite it. Previously fill 

 the space between the outer and inner case 

 with water up to the dotted line, half way 

 up the cap-valve /; which will completely 

 immerse the furnace ; and when steam is generated of sufficient elas- 

 ticity to start the engine, say seventy-five pounds per square inch, close 

 the pipes D and A, with their respective slides ; then start the engine in the 

 usual nay, by opening a communication with steam-pipe ; ; then the blowing 

 cylinders will force their charges of air through the pipe C into furnace B, 

 partly taking its course through the mass of fuel on the grates, a suiKcient 

 quantity being introduced above the fuel to burn the smoke, which can be 

 regulated by slides in the branch pipes, terminating the air-pipe C. You will 

 discover that there is no escape lor the air thus forced into the furnace, until 

 its elasticity is, by the continued blast from the blowing cylinders, a little 

 superior to the steam in the steam chamber, when the cap-valvc/'will rise from 

 its seat, and the air, flame, and gases arising from combustion will be forced 

 to pass under the edges of the said valve out into the water ; and in this process 

 all the heat generated will be imparted to the water, without the possibility of 

 escaping otherwise. 



By the repeated experiments I have heretofore made, I find that one foot of 

 air blown into the furnace to promote combustion, by the expansion it under- 

 goes, and by the addition of the gases and steam, is augmented in bulk at least 

 five times its original size, or, to speak briefly, there is five limes as much com- 

 pound steam as air forced into the furnace ; consequently, it will lake one- 

 lifth part of the power of the steam to operate the bellows, plus the friction, or 

 this is nearly the power ; but I forbear at present, nor is it necessary, to speak 

 at large on that subject in this paper. 



By a careful examination, it will be seen that the pressure of steam will 

 wholly depend upon the proportion of the size of the blowing cylinder to the 

 steam cylinder. In my engine now building, the blowing cylinders each con- 

 tain twenty cubic feet, the steam C}lindcrs each forty feet; but the steam being 

 cut ott'when the piston has made but one half its entire stroke, which reduces 

 its size, as a measure to deal out the steam, to exactly the size of the blowing 

 cylinder, the measure of the air forced in by the blowing cylinders being aug- 

 mented, by passing through the generator, to five times its bulk, has to he 

 forced into a space in the steam cylinder of just its original bulk; it will, 

 therefore, exert a force equal to fi\e atmospheres, which will be sisly pounds 

 to the square inch above the atmospheric pressure. 



This force, per inch, will not be e.xerted during the nhole length of the 

 stroke of the piston, but only half way, or to where the steam is cut oti'; and 

 at the end, its elastic force is reduced to about twenty pounds, whit:h will make 

 the average pressure fifty pounds per square inch, and the piston contains y62 

 square inches, which multiplied by .'jO, will produce -18,100 pounds — the whole 

 average force the piston moves with. It is calculated to have the engine make 

 thirty-five double strokes per minute; hence, the piston will mnvc i'lO feet per 

 same time, which multiplied by 48,100, produces iO, 202, 000 potuids : the 

 weight that the piston would lift one foot high per minute, divided by 33,00Ol 

 being what a horse-power is estimated at, gives 6I"2 horse-power for each 

 steam-cylinder. But the power abstracted to operate the blowing cylinders 

 and overcome the friction, I allow nearly equal to the power of one of the 

 cylinders; therefore I estimate the power of the engine at fil2 hoisc-power. 



The amount of fuel consumed will depend upon the amount of air forced into 

 the furnace by the blowing cylinders, and my two blowing cylinders, at evc:y 

 revolution, would force in 80 feet, if there were no leak either in piston or 

 valves, and no space between said piston and valves for the air to compress in, 

 and not be wholly forced out ; therefore, probably not more than 7 J feet will 

 be expelled each revolution of the engine ; and as it takes all the oxygen con- 

 tained in 175 feet of atmosphc'ric air to burn one pound of carbon, and .>;25 

 feet to burn one pound of hydrogen, I am of opinion, that to allow 22a feet to 

 be necessary to burn one pound of fuel, will not be allowing too much ; anil, 

 as before stated, 7.5 feet will be forced into the furnace at each revolution, it 

 will therefore lake three revolutions to burn one pound ; and, as a cord of yellow 

 pine weighs about 2,1U0 pounds, it will take (),.'i00 revolutions to burn one cord, 

 which, divided by .35, the motion of the engine per minute, will give three 

 hours for each cord'- which, compared with the engine of the stcRmer Eric/ on 



the Hudson, of little less or nearly the same power (600 horse-power), will 

 consume furty cords in ten hours, or twelve cords in the same timo my engine 

 will one cord. 



RESTORATION OF GOTHIC WORKS IN AUSTRIA. 



M'j find that the attention of the Austrian government has been attracted 

 from the research of classical ruins to the restoration of their own fine fiothic 

 monuments, some of which thnatened to be equally lost. When we remem- 

 ber the expense which was employed in the antiquities of Pola, Spalato, 

 Aquileia, Trieste, Venice, Verona, &c,, we are justified in entertaining great 

 expectations from this zeal for their national architecture. We do not know 

 whether this is one of the fruits of the I'rench mania for the Renaissance, but 

 at any rate it forms an accession to the extension of that taste for the Gothic, 

 which already in France and Norlhcrn Germany seem to promise the revival 

 of this glorious style. Few countries are more intere.-ti)ig than those of the 

 Austrian empire to the student of medieval architecture, for they stand upon 

 that debatable ground where the iMoorish and the Byzantine influence both 

 exercised control, and where the churches are not less interesting from proper 

 Gothic monuments, than from the relics of those arts which Greece, even when 

 expiring, poured forth on the western world. 



SOUTH EASTERN RAILWAY 



WOBKS XE.\R DOVER. 



Communkated lij iiii Eiit/iiieer on a ionr of inspection (J the Public Vi'orh in 

 Great Britain. 



The works upon this line of railway, under the charge of Mr. Cubitt, are 

 now proceeding with vigour, and present a thorough business-like appear- 

 ance, indicating a decision on the part of the company to complete with as 

 little ddav as possilile this line of railway, which, as the great continental 

 outlet of the l;ingdom must, when completed, assume an important station 

 among the principal lines of internal communication. 



At Dover the works which are nuder the charge of Mr. John Wright as 

 resident engineer, are very extefisi\e and also of peculiar interest; they con- 

 sist of the formation of" double (or parallel) tnuuels, together with open 

 galleries along the lace of the extensive and magnificent range of chalk 

 dills which extend fronr the harbour at Dover to the MartcUo towers east- 

 ward of Folkstouc. This very interesting portion of the line is being divided 

 into six spaces of unequal extent, three portions appropriated to tunnels, two 

 to the open galleries alternating with the tunnels, and the sixth to an open 

 cutting along that remarkable place the Warren, which is an underclitf 

 occasioned by a settlement of the chalk strata during one of those great con- 

 vulsions of nature, which causing both subsidence and elevation of the crust 

 of the earth, lias put us in possession of her intenial wealth, and given to the 

 science of geology its high importance. 



The eastern tunnel terminates at the Dover side of Shatspeare's cliff, 

 where the cutting to form the face of the tuinicl will be about 110 feet, the 

 inunense masses of chalk rock required to be removed from this s]iot, and 

 from so great a height, has led to a \cry extensive use of gunpowder for this 

 purpose, and masses containing upwards of one thousand cubic yards of 

 chalk arc at one blast precipitated from the summit to the beaoh below, there 

 to be levelled for the formation of an embankment leading to the terminus on 

 the ijuay. \\'c were fortunate enough to witness two of these blasting 

 operations on the 12tb of January, the masses to be removed were nearly 

 cubes containing about 7(10 yards each, and isolated from Ihe great body of 

 the clilV, by excavaiiiig from behind Ihcm a sullicieut space for the workmen 

 to pass and repass convcnicnily ; al the foot of the nmss to be overthrown, 

 in the above-named excavation, two borings «crc made downwards, forming 

 an angle of about thirty degrees with Ihe perpendicular, each boring being 

 fifteen feet deep ; these were then tilled, first nith six inches of tow at the 

 bottom, then JOlbs. of gunpowder w as poured in, and lastly the boles were 

 rammed to the top with rubble chalk around an iron rod, which, upon being 

 withdrawn, left a hole from the surface to the cliarge to contain the priming, 

 which consisted of Cue gunpowder; in one of Ihe holes of Ihe second mass 

 to be overthrown, the priming was conveyed lo the centre of the charge by a 

 pewter tube i -inch bore, similar to those used as gas pipes : this was done by 

 way of experiment, and appeared to answer better than priming in the 

 common wav, which commnnicatcs with the top of the charge only instead 

 of the centre. ^Vlleu all was ready and the ordir for firing the train given, 

 a most animated scene presented itself along the extensive lace of Ibc cutting 

 tlic workmen, amounting in number lo about 170, were seen scrambling and 

 climbing along the almost perpendicidar face Xi( the clifi', to attain a respectful 

 distance from the scene of action. In a few .seconds after the ignition of the 

 train, a rumbling sound, like that of extremely distant thunder was heard, 

 iiiul the next instant the whole mass was lifted bodily from its base, and in 

 fallin" a"ain, it cleft asunder from top to bottom, and opening, crumbled to 

 fragments, which poured like a Uirren* down to the beach. The charge being 

 inserted oblinucly (below the mass to be ovcrOn-owii, as before described), at 

 the same time lliat it liflcd it up, forced out at least 300 yards from below 

 its base, making a total of not less than one thousand cubic yards of chalk 

 removed with one blast, and if both charges had gene oil' simultaneously, as 

 was intended (there having been a perceptible interval between the ex- 

 plosions), a nntch greater effect would in all probability have been jiroduced, 

 as it was, however, estimating it at 1000 yards, and allowing the specific 

 gravity of chulk lo he 23, as stated by Br. Mantcllj wo bfiYO for tho weight 



