1846.'] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



9 



GREAT BRITAIN STEAM SHIP. 

 ( With an Engraving Plate I.) 



It is with great satisfaction tliat we commence the series of plales 

 illustrating this volume with a subject of so general and valuable interest 

 to engineers, as the engines of the " Great Britain." Plate I. is a c(jpper. 

 plate engraving representing the position and general arrangements of the 

 engines. The vessel is supposed to be cut a-midships ; so that one half 

 the machinery is shown ; two of the four cylinders, half the drum whicq 

 drives the endless cogged chain, &c. A full description of the Great 

 Britain was given in the last October and November numbers of this 

 journal, which it is not necessary here to report, as the engraving is 

 not sufliciently explanatory of itself. It has been carefully reduced from 

 the original drawings of the Great Britain, which were courteously placed 

 at our disposal of the purpose : the scale of the plate is a quarter of an 

 inch to the foot. 



EXPERIMENTS ON STEAM. 



A paper by M. Regnault was read at the Paris Academy of Sciences, 

 on Dec. 15, relative to his experiments on steam. The Minister of 

 Public Works assisted M. Regnault with the means of making these ex- 

 periments on an extensive and practical scale. The questions to be de- 

 termined by M. Regnault were — 1. The law which unites the tempe- 

 ratures and elastic powers of aqueous vapour at saturation. 2. The 

 quantity of heat absorbed by a kilogramme of water at degree, to be 

 converted into steam for saturation at dill'ereut degrees of pressure. 3. 

 The quantity of heat absorbed by the same quantity of water, in order 

 lo raise the temperature to the point in which it assumes the state of 

 vapour under different pressures. 4. The specific heat of aqueous va- 

 pour at different stages of density, and at different degrees of tempera- 

 ture. 5. The co-efiicients of dilatation of aqueous vapour in different 

 stages of density. In his present paper M. Regnault gives the law of 

 the elastic powers of steam up to 23 degrees cenligrade, which tempe- 

 rature corresponds to 28 atmospheres and a half. He next fixes the 

 total heat of steam taken at different pressures, from l-5th to 15 atmos- 

 pheres ; and finally, he treats of the calorific capacity of water from to 

 190 degrees. Many distinguished men have devoted their attention to the 

 elastic powers of steam. We may mention Achard, Greu, Dallon, 

 Christian, Arzberger, AVatt, Robinson, Betancourt, Schmidt, Southern, 

 Ure, Gay-Lussac, August, Kaemtz, Dulong, and Arago, the two latter 

 of whom commenced their experiments in 1S23, at the request of the Mi- 

 nister of the Interior, and published an account of thera in 1829. They 

 carried their operations up to 25 atmospheres. About the same period 

 a commission of scientific Americans performed a series of experiments 

 on this subject, but went up to only 10 atmospheres. The results, how- 

 ever, of these different experiments were not alike, consequently IM. 

 Regnault had lo take entirely new ground, greatly aided, however, by the 

 progress which science has made since the period alluded to. In his re- 

 sults he agrees most with Mi\I. Dulong and Arago, particularly as re- 

 gards high rates of pressure. Watt had supposed that the total quan- 

 tity of hejt necessary for the transformation of a kilogramme of water 

 into the state of steam was certain under a constant pressure. The num- 

 ber admitted was 650. This law, although not exemplified by any pre- 

 cise experiment, had been, until very lately, regarded as positive, and so 

 adopted in theory and practice. M. Regnault, however, has ascertained 

 that this number increases constantly from 622 under the pressure of one- 

 fifih of an atmosphere up to 670 under 15 atmospheres. At the ordi- 

 nary pressure the average of 3S experiments gives G36-37. As to the 

 calorific capacity of water, it is 1,000 between and 30 degrees, 1,005 

 between 30 and 120, 1,013 between 120 and 190. 



The Cathedral of St. Denis. — The monument erected to the memory 



of Louis XVII I. iu the vaults of the Cathedral of St. Deuis Is about being completed, 

 and, when finished, that of Charles X., his Euccessor, nill be proceeded ivith. When 

 this Is done, all the French Kings and Princes uii to lt<30 will be there represcnred either 

 by a tomb, a moutimeut, or a statue. 



CHRIST CHURCH, PLYMOUTH. 



We have received some information respecting the architecture of this 

 church, which has recently been completed, from the designs of .Air. Wight- 

 wick. The dimensions are about 70 feet by 90 feet. The style. Perpen- 

 dicular. The western front presents three entrances and three gable roofs, 

 of which the central or highest gable reaches the height of 50 feet. Be- 

 tween it and each of the wing gables rises an octagonal turret, aud at the 

 outer sides of the wing gables are pinnacles. 



It will be concluded from this description of ihe western front, that the 

 interior of the church is divided into three compartments — of these the 

 central one, or nave, is divided from the lateral aisle by piers. There are 

 five arches on either side of the nave, and over them clerestory win- 

 dows, which give the principal light ; for owing to the contiguity of 

 neighbouring buildings, there are no windows whatever iu the side aisles, 

 and consequently there is no means of lighting the church except by these 

 clerestories and the windows at the east and west ends. 



Our informant says it was absolutely necessary to introduce galleries. 

 However, it appears that the galleries are set so far back, as not to abut 

 on the piers, and as they do not cross the aisle windows (there being none 

 to be crossed,) this " absolute necessity" is not so much to be regretted as 

 it otherwise would have been. 



The architect has shown great judgment in the selection of some of his 

 details, from ancient examples. The western entrances are copied from 

 those of Tattersall Church, the crockets and finials of the octagonal turrets 

 from those which many of our readers may remember at Magdalene Col- 

 lege, Oxford. 



The nature of our information does not warrant a very decided criticism 

 on the merits of the new church — the general character of the architectural 

 details is probably unexceptionable. Unless, however, we be greatly mis- 

 taken, the building has one great fault — a show front; the elevation to- 

 wards the street exhibiting considerable pretensions, while the other sides 

 of the church are merely plain masonry. If misinformed on this point, we 

 shall be glad to be set right. If, however, the fact be as here assumed, it 

 cerlainly will materially diminish the architectural value of the building. 

 One of tlie most admirable characteristics of the old Christian architects 

 was their total freedom from pretence. They never adorned one side of a 

 church and left the other three sides plain — taking care to turn the dressy 

 side where it would be most seen. There is no ancient cathedral, minster, 

 abbey, church, or chapel in Christendom with a show side. The old 

 architects never attempted to cheat beholders into a belief that their works 

 were elaborate, when in truth they did not deserve the character. Of 

 course these remarks must not be considered to imply a censure on the 

 architecture of the Plymouth Church. The architect cannot of course be 

 blamed for the defect alluded to, if he had no power of remedying it. Still 

 it is greatly to be regretted tiiat he should have had to exert his talents 

 under circumstances which would of necessity produce an unsatisfactory 

 result. At the east end of the Church, in the place where the chancel is 

 usually built, is a " communion recess," ten feet deep. 



Since the above was in type, we have received a description of the 

 cliurch, taken from the Plymouth Journal. As however this description 

 is very similar to that given above, we avail ourselves of the following part 

 only of the extract sent to us. " The interior presents au effect of lightness 

 and elegance which is admitted by all who have seen it, aud fully justifies 

 the architect in his idea, that the details of Gothic architecture may be 

 employed in the fullest consistency with that expression of ojienuess whicli 

 should characterize a Protestant church. In fact the public of these towns 

 have now an opportunity of making a fair comparison between the pecu- 

 liar characteristic of the Camdenite structure, and tliose of the Reformed 

 Church. St. Michael's, at Stoke, and Christ Church, at Plymouth, are 

 now before them. In the former, we have the picturesque — in the latter, 

 the elegant. The first shows a handsome, though unfinished exterior; the 

 latter its single front of far more ornate character, the means of the archi- 

 tect being concentrated on one point, and that being brought to perfect 

 completion. St. Michael's is of the most simple plainness within, and 

 affects no more than a general expression of shadowed gloom. Christ 

 Church exhibits, within, the decorative amount pror..ised without, and 

 unites solemnity with grace. Though ' cheerful as the day,' it is not less, 

 as Cowper would say, the house of ' true piety.' What the cost of St. 

 Michael's may be, we have yet to learn ; but we know, that Christ Church 

 has been completed, including 85i. for extras, for only 01. 3s. 6d. above the 

 architect's estimate— the total cost of the building beiog 3,475/. The ac- 



