112 



TIIK ClVir. KNf.'INKIOK AND AKnilTI'X'rS JOUKNAL. 



[A PR 1 1., 



iiig juint-i, (he formula is cos. a — cos. b cos. c ; ;imiI (lie <i|ieriition is 

 as follows: — 



■Jth division 21 lU 35 ^V 



Constant obliquity lis O 



Va 



iif a : 



m -Si Vi 



42 21 lU 



Stli division 



Constant obliijuity (38 U 



Value of a =^ 73 55 42 



12tli division 63 31 45 



Constant obliquity (JS 



log. cos. '.)-9t;'.)G37 

 log. cos. 'J*573575 



log. COS. 9-543212 



log. COS. <)-868(551 

 log. COS. 9-573575 



log. COS. 9.44222(i 



log. COS. 9-G4908O 

 log. COS. 9*573575 



Value of a = SO 23 J U - - - log. cos. 9-222055 



We liave limited the preceding construction and calculation to three 



courses only; (his we have done for the purpose of saving room luid 



)ircven(iug confusion in (he figure; bu( from what has been effected, 



_ (he reader will readily trace the method of procedure in any other 



case. 



PROPOSED EMPLOYMENT OF VIBRATING CYLINDERS 

 FOR THE LARGEST CLASS OF MARINE ENGINES. 



The compact form of (lie vibrating cylinder engine, its light weight, 

 and (he small seclion of the vessel which it occupies, together with 

 the advantage of having the strain from the thrust or pull of (he pis(on 

 endiely within i(s own framing, and no( pardally transferred to (he 

 kelsons of the vessel, as is the case in the beam engine; seem (o 

 point it out as jieculiarly applicable to steam navigiition, and espe- 

 cially (o (hose gigantic ellbrls which are now making to extend our 

 iulercourse with distant countries, where the advantage of having 

 large ))ower in small space cannot be too highly appreciated, as the 

 various efforts of the most celebrated makers to effect (hat object suf- 

 ficiently testify. 



Various reasons however have been assigned why this form of en- 

 gine should not succeed on a large scale, and these 1 shall endeavour 

 to notice and refute. 



1st. The great weight of the valve casing and slide on one side has 

 been objected to as destroying the equilibrium of the cylinder, and 

 wearing the cylinder and stuffing box unequally. 



"2d. The diflicuUy of casting the cylinder and hollow gudgeons 

 sound, and the impossibility of repairing them in case of a failure. 



:jd. The disadvantage of passing the steam through the gudgeons at 

 all, owing to the heat occasioning an unnecessary friction. 



4th. The loss of power in communicating a vibrating motion to such 

 a large body as the cylinder. And lastly, the difficulty of jiacking. 



Now if the above named objections can be got over, which 1 think 

 there will be littU; difficulty in doing, we shall then have an engine free 

 from all the disadvantages of increased friction and short connecting 

 rods ; more compact in its form, and less exposed above the water 

 fine than any yet before the public, and consequentiy more eligible for 

 the purpose of commerce or war. 



To get rid then of the first objection, I propose to dispense with tlie 

 slide altogether, and to substitute in its place four double -beat valves 

 as used in the Cornish engines; one toji and bottom of the cylinder on 

 either side, two being steam and two exhaustion valves. 



I conceive there are many advantages to be derived from this form 

 and arrangement of the valves. Thus, the steam valves would also 

 serve as expansion valves, as being independent of the others there 

 Would tie no dillicnlty in shutting them at any point of the u|) or down 

 stroke of (he pis(on, affording us (he op])ortunity of so adjusting them, 

 as to avail ourselves to any desired extent of the principle of expan- 

 sion. The exhaustion valves would have the same ficility of adjust- 

 ment, so that we should be enabled to open and shut the passage to 

 the condenser at the point which would ensure the most effective work- 

 ing of the engine; such valves also afford great facility of repair; 

 with the additional advantage of one man being able to handhUjotli 

 engines, although the cylinders were ten feet diameter, as such valves 

 being almost balanced, lift or open, with the slightest exertion. 



"2(1. I would cast the gudgeons on a separate circular frame, just 

 large enough to encircle the cylinder and to which the cylinder should 

 be securely bolted by a strong projecting flange; this would occuiiy a 

 very lillle additional breaddi, and' would entirely g(-t over that dilii- 

 cully. 



:jr(l. 1 do not know that passing the ste.im through the gudgeons is 

 a serious evil, but at all events it can be very easily obviai'ed. 



Let the joint and stufl" box be placed on the end of the gudgeon as 



usual, so as to be concentric and firnify secured, and let a flat pipe b^ 

 carried up till sufficiently clear of the pluininer-block cover, and then 

 bent over and secured to the body of the cyliiuler, when it can be easily 

 connected with either set of valves; by this arrangement the steam 

 does not pass through the gudgeons at all. 



4tli. This I have often heard urged as an insuperable obstacle to the 

 successful a|)plication of (his form of engine, but when we consider 

 that the working beams, crossheads, ice, in almost eveiy case exceed 

 the weight of the cyliiuler — further that the beams, crossheads, &c., 

 must in all cases move through twice the space, and in many cases 

 through three times the space of the vibrating cylinder for the same 

 length of stroke, it will then appear plainly that this objection has no 

 foundation, the loss of power from the saiiu? cause being evidently less 

 than in a common engine. 



The last objection, vh., the dilliculty of packing, seems scarcely 

 worth notice, as it has been perfectly overcome in numerous boats now 

 running. 



The stuliiug box ought to be considerably deeper than in conmion 

 engines, and the piston rod somewhat stronger. 



The air pump, feed and bilge pumps can be easily worked from the 

 intermediate shaft, as frequently done. But I should greatly prefer 

 having a separate steam cylinder to work all those jiumps, working in 

 connection with and at pleasure, detachable from the main cylinders, 

 this would get rid of the crank or eccentric on the intermediate shaft, 

 which is to a certain degree objectionatMe. It might be so arranged 

 as to be quite out of the reach of shot, and would not occupy any 

 additional space on the floor of the vessel beyond that occupied by 

 the engine framing; the fotlowing striking advantages wou'd accrue 

 from this arrangement ; we should be enabled to keep up the steam 

 and preserve s \ acuum for any length of time, so as to start at a mo- 

 ment's notice ; and secondly, whatl consider of far greater imjiortancc, 

 the turn of a cock, or opening of a valve might convert the air pump 

 into an immense bilge pump, with an available power to work it, and 

 suflicient to keep tlie vessel clear under almost any circumstances. 

 The additional security to the shipowners, and safety to the jiasseugers, 

 which this would ensure in case of the vessel taking ground, or in 

 other circumstances when it might be inconvenient or impossible to 

 work the engines, cannot be too highly estimated ; and Ihave no doubt 

 there are many naval men who at one time or other would gladly 

 have availed themselves of such a power. But if this arrangement 

 be considered too decided an innovation, they can be worked in the 

 usual manner. 



In conclusion, I see no difficuKy in the manufacture, nor any reason 

 to adprehend a failure ; and as such an engine would occupy not more 

 than half the space of a coinmon beam engine, would weigh very con- 

 siderably less, and would, as bel'oie mentioned, be free from all the 

 disadvantages of increased fricfion or short connecting rods, with the 

 advantage of being less exposed above the water line ; and lastly, 

 could be made for quite as little, if not less expense ; it is well worthy 

 of (he a((eii(ion of (he heads of our naval es(ablishment, and of steam 

 boat proprieiors in general, and if (here be any thing against it which 

 I have overlooked, perhajs some of your numerous correspondents 

 could point out where the fault lies. 



A. S. 

 Pimlico, Muic/i 17, 1840. 



TABLE OF ARCHITECTS WHO HAVE DIED IN THE 

 ISTH AND 19th centuries. 

 By W. H. Leeds. 

 Lmpeufect as the following Table is, in Itnai labor might be its motto, 

 since the drawing it up lias cost far more pains and research than it 

 ought to have done, or would have done, had not archi(ec(ural biogra- 

 jdiy been notoriously slighted. Relative to Italian architects and 

 a few others of jireceding periods, information may be met with in 

 general biograjihical works, because the materials for such articles 

 are abundantly supplied by Vasari, Baldinucci, and other writers of 

 that class ; but, with here and there an exception, such biography 

 becomes nun-e and more meagre, precisely when it might be expected 

 to be more copious and satisfactory, namely, as we approach our owu 

 times. Not having the original work by Militia to refer to, I do 

 not precisely know which are the " Additional Lives," inserted by 

 his English translator, but it certainly does not say much for either 

 the diligence or judgment shown by her, when w'C find such names 

 ao (hose of Langhans, An(oine, and Ledoux omitted, while such a 

 person as ,loel Johnson, is deemed worthy of notice. The ap- 

 pendix to (^ualrenure de Quincy's "Vies des Architectes," gives 

 a few notices of architects who lived in the two last centuries, 

 yet in only one or two instances is there a date ,of any kind, which 

 is certainly a more original than laudable mode of treating biogra- 

 phy and history. Even Nagler's work, which professes to give 



