1846.] 



THE CIVIL ENGINEEER AND ARCHITECT'S JOURNAL 



155 



take not, claims Mr. V^yndham Harding for its author. The style pos- 

 sesses the clearness, and the views are expressed with the moderation, by 

 which Mr. Harding's dissertations on the gauge controversy have been 

 characterised. Without involving ourselves in the discussion, vpe cannot 

 help expressing an opinion that those vfho have read the " Observations" 

 of the Great Western Railway Company ought certainly to examine the 

 present pamphlet, which meets each argument consecutively, and treats 

 the general question with great perspicuity. We wish, however, more had 

 been said about the Intermediate Gauge. There are many competent 

 persons — Messrs. Bury, Vignoles, and Cubitt, Col. Landmann, and Gene- 

 ral Pasley are among (be number — who think the broad gauge too broad, 

 and the narrow gauge too narrow. In the present pamphlet this opinion 

 is dismissed in twelve lines; in the Commissioners' Report scarcely more 

 space is occupied with it, and the view there taken is supported by very 

 inadequate and inconclusive arguments. 



Tables and Rules for facilitating the Calmlation qf Earthwork, Sjc, of 

 Railways, Roads, and Canals. A Iso essays on the prismoidal formula, and on 

 the power required upon inclined planes. By J. B. Hdntinoton, C.E. 

 Weale, Holborn, 18-16. 12mo. pp. 286. 



The object of this work in some measure resembles that of a smaller 

 one by Mr. Hughes, reviewed in the March number of this Journal. The 

 present treatise, however, embraces several subjects in addition to the cal- 

 cnlation of earthworks. Tables are given for the calculation of the areas 

 of slopes, the offsets and radii of curves, &c. The first 170 pages are 

 occupied by the tables for the cubic contents of cuttings and embankments. 

 Kext follows a demonstration of the prismoidal formula and illustrations 

 of the accuracy of the calculation by this method compared with that 

 generally used by contractors. After explaining the method of using the 

 foregoing tables, the author gives a description of a graduated scale for 

 measuring earthworks, without the necessity of referring to tables. A 

 woodcut, respresenting one of these scales made by Elliot, accompanies 

 the following description : — 



" I now proceed to give an explanation of a scale for measuring earth- 

 ■work, which I have successfully used on the Eastern Counties Railway. 

 The vertical and horizontal scales, and also the base and slope, must be pre- 

 viously determined for each scale, and then a set can be formed embracing 

 the required slopes of the railway. My scales were made four in number, 

 for base 34 ; slopes 1, IJ, IJ, and 2 to 1 ; and on the back of each was 

 properly described the slope, base, and vertfcal and horizontal scales to 

 which they were applicable. All the dimensions were taken in yards lineal, 

 superficial, or cubical, as required ; the application being precisely the same 

 as the use of the tables, and the rules being the same to find the ai'ea, using 

 2 as a co-efScient instead of 6. Owing to the fineness of the graduations, 

 1 would not advise, to insure accuracy, that the vertical scale be made less 

 than 40 feet to 1 inch, and, generally, the larger the better. 20 feet to 1 inch 

 vertical is a good working scale. The lengths can be made to suit conve- 

 nience. There is no necessity to measure the heights or lengths previously, 

 and the same form must be used as before described. 



To Measure a Cutting by the Scale. — Apply the zero of the scale of sec- 

 tional areas vertically to the gradient or formation line, and read off where 

 the surface line intersects ; put this in column 1 or 2, as the case requires : 

 then, at the smaller end of the prismoid, upon the scale of vertical yards, 

 with zero on the surface line, observe where the gradient intersects, then 

 place the same point of intersection on the gradient at the other end, and 

 read off above the zero on the scale of differential areas, where the surface 

 line insersects; put this in column 4, and then, having measured all the 

 lengths by the scale of horizontal yards, proceed as in the use of the tables. 

 To save time, it is desirable to take a pair of dividers, and mark off at each 

 division the difference of the heights in succession, and then the differential 

 scale above zero need only be applied. 



This method of computing cubic contents of cuttings and embankments 

 is very expeditious with a little practice, and is quite as accurate, and gene- 

 rally more so, than the calculating by feet and the tables ; because, in a 

 working section, the paints of intersection of the scale and surface line can 

 be estimated readily by the eye ; but, in using an ordinary scale of equal 

 parts, we are compelled to neglect the fractional parts of a foot." 



The above extract is followed by tables of areas required on a railway 

 for cuttings and embankments of various heights and slopes; tables for 

 estimating the superficies of slopes ; for finding the radius of a curve of 

 which the chord and the angle contained between the tangents to the two 

 extreme points of the arc are known, &c. 



The part of the work which refers to mensuration is followed by essays 

 on the resistances to locomotives, and the relation of the power of the 

 engines to those resistances. These essays, however, are not altogether 

 satisfactory ; for instance, the resistances in question are stated to be these 

 threej— the friction of the carriages, &c., the resistance of air, and the re- 



solved part of the weight on an incline ; the author has, however, neglected 

 the resistance due to the blast-pipe, which frequently at high velocities 

 causes a pressure of 8 or 9 lb. per square inch on the piston. The follow.- 

 ing passage is altogether erroneous— the author is calculating " power" 

 necessary for drawing a given load ; D is the diameter of the driving 

 wheel, a the area of the piston, I the length of the stroke : — 



" Letp represent the pressure (CO lb. on the inch), and let the previous 

 notation be used, then the general expression of the power hpal-^T> for one 

 cylinder only. The ratio between the greatest effect of one crank, and the 

 mean effect of two acting simultaneously at tight angles to each other, is 

 nearly as 10 to 16 ; and adopting this proportion, we have 1-6 x^aA^D = 

 power of two cylinders." 



This short extract contains three errors, either of which would be fatal 

 to the conclusion arrived at. First, the pressure in the cylinder is sup- 

 posed to be the same as that in the boiler, whereas the relation of these 

 two pressures to each other depends on the velocity or number of strokes 

 per minute ; for the more frequently the cylinders have to be filled in a 

 minute, the more will the steam be dilated in passing from the boiler. 

 Next, the "general expression of the power" po/-r-D is erroneous, for the 

 relation of the pressure on the piston to that exerted by the driving wheel 

 depends on the proportion of the distance traversed by the piston, to that 

 traversed by a point in the circumference of the driving wheel ; conse- 

 quently, supposing the above formula correct in all other respects, we must 

 substitute the length of the circumference for that of D the diameter. 

 Lastly, the ratio 10 : 16 could not have been arrived at sxcept by a stati- 

 cal process, that is, by supposing the engine not in motion ; for when it 

 is moving, the ratio will depend on excessively complicated relations 

 between the velocity, the load, &C. ; moreover, the application of this rela- 

 tion here is hopelessly erroneous, for {inter alia) it is in direct opposition to 

 the law that in machines force is neither gained nor lost by transmission, 

 excepting so much of it as is absorbed by friction of the mechanical 

 organs. 



It is due, however, to the author to state, that the theoretical essays are 

 not considered as integral portions of the work, and that in the part which 

 refers to mensuration everything has been done to facilitate calculation and 

 to render the tables convenient for reference. 



Ancient and Modern Architecture ; consisting of views, plans, tfc. 

 Edited by M. Gailhabaud. Parts 43, 44, and 45 ; quarto. Didot. 1846. 

 The concluding parts of the second volume of this series, which has 

 be^n before favourably noticed in this Journal, are now before us. They 

 contain views, sections, and details of the Treasury of Atrens, at Mycenaa, 

 a monument of Pelasgian architecture, and five plates, illustrating the 

 Church of St. Francis, at Assisi, in Italy, built in the Pointed style of the 

 thirteenth century. We have little to add to our former notices, except 

 the necessity of making the plates architectural instead of pictorial seems 

 to have been more carefully regarded in the latter parts of the work than 

 in the commencement of it. The following extract from the description of 

 the church at Assisi may suggest some reflections to those who advocate 

 the universal adoption of high roofs in Pointed architecture :— 



" The lofty gable which surmounts the front does not attain the object 

 aimed at by the architects of the North in the pointed forms of their Gothic 

 fronts. The climate of northern countries required the roof to have a very 

 high pitch ; the architectural decorations were conceived so as to harmonise 

 with this necessity. In Italy it had always been usual to cover buildings 

 with low roofs ; and architects even in the Middle Ages should have con- 

 formed to this long establised practice. This high and useless gable, form- 

 ing an isolated wall of a very uppleasing efiect, and exposed to all the winds 

 of heaven, is an anomaly that would seem to indicate th? northern origin of 

 the architect of the church of Assisi. .... In the 

 upper nave, the trefoil arches, the tall openwork gables, the capitals with 

 vegetable ornaments, all so common then in the North, are too boldly em- 

 ployed to be attributed to Italians, who were then novices in this Northern 

 style. Let us add, that the muUions of the windows have the shape and outline 

 of those executed at the same date in France and Germany ; and that this 

 edifice is the only one beyond the Alps that contains a series of painted 

 windows so complete and so strictly in keeping with the general cha- 

 racter of the building. The Pointed style was still a novelty in Italy at the 

 beginning of the thirteenth century, when the church of Assisi was built ; it 

 was called tedesco, or German, and only a few essays had been made. At 

 this epoch, what Italian artist could have conceived so perfect, so well-pro- 

 portioned a whole, in a style then quite new to him ? The isolated gable, 

 which serves no useful purpose in the cHmate of Italy, though so appropriate 

 in the North, seems to prove the northern origin of the architect, who could 

 not allow himself to disfigure the pointed forms to which he was accustomed, 

 by reducing them to the low pitch of Italian roofs — a modification which 

 Niccola Pisano introduced in Gothic architecture, when he built the charcb. 



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