1849.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



3J5 



friend to arcliitects, though it may he a stern one. Were its les- 

 Bons attended to, it would elevnte them to the rank of artists; not 

 the mere nominal rank, as at present, where the term artist is hut 

 a conventional one, bestowed hy courtesy on almost any one who 

 carries on business comnie ilfaiit, without beinj; guilty of the horrid 

 vulgarity of keeping a shop; but to the real rank of truthful and 

 earnest followers of their art, — faithful and devoted to it, rejoicing 

 in its advance and successes even when they did not participate in 

 them personally. 



When criticism is erroneous, let its errors be fairly exposed; 

 when it is unjust, let its injustice he shown and reprimanded with 

 all the severity the case merits; — but to declaim against, or ratlier 

 sneer at, criticism as something that is uniformly mischievously 

 officious and impertinent — as architects appear to be disposed to do 

 — is both illiberal and unwise. If — as some of them all but di- 

 rectly saj' — it is themselves alone who can be competent judges of 

 architecture, and that they alone are properly capable of directing 

 public taste in regard to it, they are surely guilty of a very gross 

 dereliction of duty in suffering spurious criticism to be dissemi- 

 nated, while they, indifferent to the ill consequences arising to 

 their art from such pseudo-criticism, withhold the genuine. Their 

 own words condemn those in the profession who represent architec- 

 tural criticism to be, almost without exception — for they make no 

 exceptions — the reverse of what it ought to be; since tliey plainly 

 intimate that there is very great need for better criticism — for such 

 as they alone are capable of producing, yet instead of doing so, 

 preserve an obstinate silence; leaving the public to be misled, by 

 various shallow and erroneous opinions, merely because they them- 

 selves are too indolent to contradict them, — for to question their 

 ability to do so would be deemed the height of presumption. 



It is, perhaps, owing to their antipathy to criticism and every- 

 thing connected with it, that, when they do chance to take up the 

 pen, professional men very seldom care to display any particular 

 critical power, by speaking of works of architecture as woi-ks of 

 art, and by deliberately pausing upon, and intelligently explaining 

 their respective beauties or defects. Hence a certain degree of 

 dogmatism, or the appearance of it, in their writings; for however 

 just they may be in themselves, remarks which amount to no more 

 than the brief and bare enunciation of opinion, or of its verdicts, 

 must almost inevitably partake of dogmatism in their tone. We 

 are in a manner authoritatively commanded to admire or dis- 

 approve upon the mere ipse dixit <Tf the writer, without argument 

 of any sort being employed for the purpose of convincing us. Far 

 — very far are we from wishing to insinuate that it is pi-ofessional 

 men alone who deal only in assertion when they should give us 

 something like adequate reasons and proofs. But they have surely 

 little right to complain of architectural criticism being for the 

 most part so feeble and unsatisfactory as it is, if they allow it to 

 continue what it is, by not even so much as endeavouring to im- 

 prove it. If they think that by merely sneering at, and affecting 

 to despise bad criticism — which all the while they leave to cor- 

 rupt public taste — they can put it down, they are greatly mis- 

 taken. 



DISCHARGE OF WATER FROM RESERVOIRS. 



The Thinnj of the Contrdction of the Movement of Water flowing 

 from Apertures in thin Plates, in a Reservoir in which the Surface 

 of the 11'aler is maintained at a constant altitude. By J. Bayer, 

 Lieutenant. (Translated for this Journal from Crelle's '•Journal 

 fiir die Baukunst.' Band 25.) 



{Concluded from page 203.) 



For computing the quantity of discharge for less altitudes of 

 pressure, the sinking of the level, as already mentioned, must be 

 taken into consideration. It can be easily ascertained that in 

 Table I., for m = 5, the co-efficient k'^ '6029 remains invariable, 

 as the altitude of pressure of tlie mean value of the water level 

 before and after sinking is assumed, and equation (</)§]! applies. 

 Take therefore H for the altitude before, H" after, the sinking. 

 Then for the "less altitudes," 



Q = •6029V(4i,).i;|[5(H + H") + /]f-['(II + H")]e|. 



As for greater altitudes, as soon as the sinking of the level no 

 longer takes place, H = H", and this equation becomes the equa- 

 ti"" (i/i § 11) above; and ensures general accuracy when it is 

 employed for greater altitudes, with the modification" that the co- 

 efficient corresponding to the quantity m be taken from Table I. 



In order to make a more extended application of the equation 

 (A), there are here given the computations from twenty-four expe- 

 riments with square orifices (the side of the square being •2mtr.) 

 Tliese experiments are given by Poncelet in Table iV. of his 

 work. 



Table IIL 



The mean error above is -274 liter. The probable error is -185 liter. 



The measurement of the altitude in relation to the surface of 

 the water before sinking has various difficulties: so tliat for prac- 

 tical apiilication it is necessary to be able to compute the quantity 

 of discharge by the altitude of pressure for the level after sinking, 

 the measurement being taken immediately above the orifice. When 

 the equation (i), § 11, is applied to this purpose, and the corre- 

 sponding co-efficient designated by c, we have 



Q = <-/-V{+i/(n" + J/)}. 



The co-efficient c may now be found. This is easily obtained by 

 Table I. hy putting ni + l, instead of m. For instance, when 



H"=-0136, — - = -068 = m, and m + l = 1-038; and for this ratio 



Table I. gives the value of c = -5950. To show the agreement of 

 this method with the experiments in Table III., the following 

 table gives, side by side, tlie co-efficients determined from experi- 

 ment and calculated by the above method. 



The greatest discrepancy from experiment does not exceed ^ per 

 cent. For greater altitudes equation ()) is directly applicable. It 

 therefore extends to all practical cases for all altitudes, if for the 

 less altitudes tlie co-efficients corresponding to m + 1, and for 

 greater altitudes that corresponding to ni, be taken. 



AVhen the quantity of discharge Q has been found in equation 

 (i), it can be substituted in (A) to find H, the altitude of pressure 

 of the water-level before sinking. 



13. 



77(6 Co-effcient of Contraction for Rectanyalar Orifices. 



When W signifies the co-efficient for rectangular, k as before for 

 square, orifices, we have as in equation {d) of the foregoing para- 

 graph 



a:/:,v„ k[i 



y = 



yrV, 



A-/^ /H, 



7r V H, 



