MS 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



L-Mav, 



= + 



Rsin (a — fl) — rsin (a— fl) (R— r) sini sin >;> | 



L / cos <p J [ 



:(!+) 



/ C06 (p 



I = 4? in. = 3'5feet; (K— r) =: 3 feet 



- sin ip = -lOCO, wliicli is the circular measure of 9° 30' 40" 



ii/'sincp) 

 cos <^ 

 and <p — 5i° 13' 



rsii 



19", 



1 + 



Qii 



J r sin/"' sin <p 

 36 X sin(- sin (pj 



= 3 0558 ; 



=: 3-403 in. = 34 in. nearly. 



-^30558 



Nosv, manifestly, PQ ; pij{l) = L sec * ; L sec cp = sec * ; sec 

 .sec* ^^ sec (.19° 23' 7") 



or, PQ = ; 



— 47-03 =: 47 



nearly.. (15) 



sec cp ' sec (55" 13' 49") 



If tlie "wiiidina; strips" be applied in the manner directed by 

 .Mr. Buck, the difference in the widths of the two ends of the one 

 that has not parallel sides ought to be 3-4 in., instead of 3 inches 

 as there pven. 



If, on the contrary, the winding strips be so ap])lied that the 

 distance of the intradosal ends A, C, and also the distance of the 

 e.\tradosal ends B, D, be 42 in. apart, the twist (/tan 3) = 3-05 in. 

 is quite correct. If AC = 42 in., and BD ^ 47 in., tlien we get 

 for the twist 3-05 x J^= 3-41 in., which differs only by -j^th of an 

 inch from the value of Q?i found in (15). 



It is quite true, when an arch-stone for an oblique bridge 

 (not a quoin) has been properly formed, that the length of the ex- 

 tradosal arris I'Q will be greater than the intradosal urrisp/] of the 

 same bed, in the proportion of sec* : sec<p. But, on the otlier 

 hand, the sole use of the winding strips is to obtain two straight 

 lines a certain distance apart, such that if two other straight 

 lines be drawn parallel to them through a given point, these two 

 straight lines may contain a given angle. 



Fif. 4. 



If tangents be drawn to the extradosal and intradosal helices at 

 the points E, D, corresponding to one position of the arm BD, 

 these tangents will be inclined at an angle * — ip. Hence, if the 

 winding strips are to be applied paratkl at a distance (R-r), and 

 in the direction of the length of the stone, make the angle hoa =r 

 * — <p = 5; take oa = the length of the rules, and draw ub at right 

 angles to oa. Then ah = oa tan 5 is the required twist. Again, if 

 the strips are to be applied across the stone, they must each be in 

 length ^ R - r. Suppose they are to be applied parallel, and at a 

 distance / = oa' ; draw a'b' at right angles to oa' meeting ob' in b' ; 

 then a'b' will be the e.xcess in breadth of one end of the rule over 

 the breadth of the other end of the same rule. 



In Mr. Buck's Essay, pages 13, 22, and 27, the difference of -j^ths 

 of an inch in 3 inches appears to be worthy of notice; but it may 

 be remarked that the obliquity of the bridge in this e.\ample is 30°. 

 In the generality of cases, the difference of the twist would not be 

 nearly so great as in the above example ; but as it is both more 

 accurate and more convenient to apply the winding strips in pa- 

 rallel directions, there appears to be no reason why any trouble 

 should be taken to calculate the divergence of them. 



The value of Qn at (14) may be put under the form 



?sin{- 8in<p} 



IC""*) J 



2 = *^l-ftan^<p nearly 



el 



el 

 = — sin 26 = 3-408 inches 

 2r 



■ sin 9 cos 



r 



(since <f is never much greater than 45°, and r is always much 

 greater than /). 



St. John's College, March, 1849. 



REVICWS. 



A Dictionary of Architecture, Decorative and Constructive, cS'C. 

 By M'alter Bebnan. Part I. 18mo. London: Williams and 

 Co., 1849. 



^Ve have here a novelty, — a novelty, at least, in its shape, for 

 although we have had more than one dictionary of the kind before, 

 this is, as far as we are aware, the very first that has appeared in 

 so convenient and popular a form. It goes, perhaps, to tlie oppo- 

 site extreme from some of its predecessors; and we think that a 

 size larger — one adapted to the book-shelf, rather than the pocket 

 — would have been preferable, and if similarly printed in double 

 columns, quite as economical. Judging from this First Part, which 

 though it contains sixty-four pages, goes no further than the term 

 "Architholus," the volume must when completed be an inordinately 

 bulky one, — unless it be intended that the work shall eventually 

 form more than one volume, of which however no intimation is 

 given; neither is it stated in how many parts it will be completed. 

 What is chiefly certain is, that it is designed to be a popular manual 

 for the use of artificers and workmen, as well as architects, en- 

 gineers, and students of architecture; which being the case, w-e 

 cannot help being of opinion that the editor has overdone it, and 

 in his ambition to introduce "many hundred words that have not 

 been inserted in any previous architectural dictionary," has cram- 

 med into it a great many which are quite out of place except in a 

 professedly archaeological glossary. To give those terms belonging 

 to mediiev'al architecture which are now in use, is proper enough; 

 but to thrust in those which have long been altogetlier obsolete, 

 which cannot be now revived, and which are not at all needed, the 

 same things being now described by more familiar words, is not 

 only injudicious as far as the work is concerned, but injudicious in 

 its principle, inasmuch as instead of enlarging and enriching, it 

 only encumbers the vocabulary of the art with antiquated and 

 useless lumber. 'Whether, as it certainly ought to do, this dic- 

 tionary will give us such really convenient and useful terms as 

 "Astylar," and several others that ha; e been employed by recent 

 writers, remains to be seen when it shall have been moi-e advanced. 

 ■We find the term "iEsthetics," but the definition — such as it is — 

 is only a borrowed quotation; from whom is not said, but <ippa- 

 rently from Mr. Joseph Ciwilt, for if the words be not precisely 

 the same, they certainly express his sneering opinion of a term 

 which, in the glossary appended to his treatise on "The Orders," 

 Mr. Leeds has shown to be singularly expressive and useful. 



The explanation of the term "Anti-Vitruvian" is also partly bor- 

 rowed, and apparently from the same source, the remark printed 

 as a quotation being as follows: "Erroneous opinions adverse to 

 the classical authority of Vitruvius on architectural topics, ex- 

 pressed by some modern professors to attract notoriety " This 

 seems to be pointed against Professor Hosking; but others, among 

 whom are both Fergusson and our own Candidus, have been 

 equally strong, therefore equally erroneous, and no doubt from the 

 same unlucky ambition of "attracting notoriety." Yet, after all, 

 it may be questioned whether error does not lie rather on the side 

 of Vitruvius's admirers, — his defenders we cannot possibly call 

 them, since they say nothing whatever to rebut the sneers of 

 his iwtoriety-seeking detracters. Now, if any one be Quixotic 

 enough to take up his cudgel fairly in behalf of Vitruvius, and in 

 good earnest belabour with it his tiepreciators, let him do so; but 

 the merely calling their opinions erroneous is not very far from 

 admitting them to be correct; nor has Mr. Bernan attempted to 

 settle the dispute. AVe rather fancy that some of the remarks 

 which he himself has occasionally indulged in, w ill, if they do not 

 actually involve him in dispute, prove not a little offensive to 

 many. The following, for instance, which occurs under the term 

 "Architect," is tolerably strong and pungent: "In spite of the 

 opinion of the ignorant public, re-echoed by the dull and costive- 

 brained (!) of the profession, which confounds the means with the 

 end, the merit and fame of an architect must rest on his talent for 

 invention ;" — the italics are not ours — "without it all the construc- 

 tive knowledge of his age will not raise him above the rank of a 

 builder-mechanic: and he alone is to be accounted happy in his 

 art to whom the gods have granted the creative spirit. The su- 

 premacy of the gift is apparent from its rarity." — Bravo! Bernan: 

 for that matches Fergusson's "monkey styles of modern Europe;" 

 or the piquant escapade in Leeds's treatise on "The Orders," viz., 

 where copyism is defined to be the process for converting design 

 into manufacture, and an architect into a machine. Verily, ar- 

 chitectural heresy seems to be spreading — some will say, most 

 alarmingly, — or as others will reply in rhyme, most charmingly. 

 "Amateur-Architects" are treated by Mr. Bernan more mildly than 



