1 840.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



209 



menf, — I mean the use of bladder colours, — and however gross the 

 abuse, however clear the demonstration of its ill elfects, I know suffi- 

 cient of artisls to doubt whether practice will accompany conviction. 



The painters of Cemiini's day — and I imagine the practice was 

 equally antecedent and subsequent thereto — used powder colours 

 ground, as with us, iuipalpably in turpentine or rectified naphth.j, and 

 very carefully preserved them in covered vases or bottles ; tlu-y fre- 

 quently kept them also under water. Now any and every pigment 

 thus treated would dry too fast by half iu Italy, and consequently oil, 

 as a softener, would be a sine qua non. Indeed, Wilkie assured me, 

 in 1S21, he had seen olive oil used, by necessity, to prevent drying. 

 Now what is our practice, in an hyperborean climate obviously de- 

 manding less oil and more forcing / Why, from sheer indolence and 

 a foolish impression of saving time, we fly to bladder colours saturated 

 with oil, and often ciianged by it (as in lakis) into a real analogy of 

 soap ; the colourman of course using such oil ' as remains greeu the 

 longest. Here, then, in opposition to climate and common sense, we 

 use a profusion of the noxious agency, and increase the evil by adding 

 bkachiU oil, and dry the whole by boiled oil and McGelp. Is this 

 rational, or is it the" acme of human absurdity ? Habit and prejudice 

 go far, and yet surely no intelligent artist can fail to see this. Still 

 demonstration is better than asseition. Let him try, then, the ancitnt 

 practice and modern one in juxta-position ; let him rub a little Like, 

 finely ground in turpentine and quite dry, with a little copal varnish, 

 and it will dry too fast for any man's use,^ — he may now add oil here, 

 bv the drop, and he will see at onc(- its beautiful powers, and, more- 

 over, this bad dryer dries at his pleasure: now reverse the experi- 

 ment, follow the modern practice — take flake white from the bladder, 

 and one of the best of dryers requires from twenty-five to forty-eight 

 hours (if flooded with oil) in defiance of copal, that is, what is called 

 cupal. 



Practical experience, a thousand times repeated, teaches me that if 

 Correggio, Anselnii, and Rubens could rise Irom the tomb and give to 

 a modern English artist the identical vehicle each had used, (although 

 he would improve in tone, brightness, depth, and impasta,) he would 

 not make a permanent picture, much less so permanent an one as they 

 did; nor could they do so, in this climate, with our bladder colours 

 and abuse of oil; while, the same experience tells me as clearly, by 

 inversing the practice, returning to the ancient use of powder colours, 

 and using oil, as Merimee would copal, to "brighten colours," to give 

 body, richness, and standing out power, this artist would paint, in de- 

 fiance of climate, as permanently as they did, and, maugre the little 

 trouble of mixing on the palette, in half the time he does now. 

 Tubes' it is needless to name ; no greater curse was ever invented to 

 swamp an art. I have again and again repeated the assertion that 

 permanence in oil painting is dependent on vehicle alone; bearing 

 this in mind and inversing the order of manipulation, remembering 

 that the resinous principle is the source of preservation — as wax and 

 resin were in Greek pictures, — and that no chemical agency exists to 

 supply their places, few artists will make changeable ones. 



'i'o show, however, how readily we may be mislead, and how easily 

 even the possessors of a really more valuable secret than that which 

 Leonardo da Vinci bequeathed to posterity for refining oil, might and 

 did fall into error. Carry this principle to excess in a simple expe- 

 riment, — flake white in the vehicle alone use no raw oil, and 

 however rapidly it may dry, however beautiful it may look, however 

 hard, without crack, it may become, it changes more rapidly than lead 

 and raw oil before sulphuretted hydrogen, — and why f the resin, dis- 

 solved in the oil, has so perfectly overcome the rising that nilhoui 

 fresh oil you have neither the luscious richness of texture nor skin 

 enough to preserve it from the action of the gas; ergo, this small 

 quantity of raw oil is a sine qua non of permanence and beauty com- 

 bined, and it is the excess of oil alone I have endeavoured to combat; 

 that excess which Haydon vaunts at the moment be gives an example 

 of the value of its absence ;;; totu. And these experiments refer 

 more speci dly to lead and those metallic colours which readily oxy- 

 genize oil and increase its skinning power: lead being, in flake white, 

 the beacon ai.d the guide. So special, indeed,doL's all my experience 

 bespeak it, 1 hope to be the means of destroying the use of lead 

 ground in oil alone, as fervently as I hope to destroy the use of tubes, 

 which are adapted only for plaster of Paris and McGelp men. 



Davy blundered on that which Reynolds'' saw distinctly and practi- 

 cally; but, unfortunately, his hasty temperament and vacillating mind 

 led him into false, blind, and stupid experiment. Neither usphaltum 



4 Hence the colourman values nut oil of which he is necessarily as liheral as possible. 



j To my certain knuwledj^e one colourman varnishes his tubes internally ; while 

 another has received orders, ' more than once,' •* not to send old tubes," under the sup- 

 poaitioQ that old and dirty ones had really been used, from the deteriorated state uf the 

 colours. 



c lleynolds saw correctly the positive use of re?in and varnish, in some way or other, 

 by the older painters, but misapplied both. 



nor McGelp, bad as tliey are, could have cracked in any other 

 hands as in those of Sir Joshua ; first, because he was perfectly igno- 

 rant of any agent capable of giving them toughness without horny 

 skin ; and secondly, because even had he possessed such an agency, 

 his very method of pointing ensured crack, — egg, .Venice turpentine, 

 varnish, wax, &c., touchi d upon each other, and therefore drying' in 

 various degrees and intensities, as any man may readily conceive him- 

 self; indeed, scores of pictures have cracked with simple varnishes, 

 not in themselves disposed to crack, from this cause, wlien, had they 

 pervaded the whole texture of a picture, ever so slightly, they would 

 never have cracked at all. 



Much is said and written daily about the march of science and pro- 

 gress of art, but I am afraid we have many Sir Joshuas, without a 

 tithe of his real worth, and more than one Davy, in assumption, with 

 none of bis naturally bright mind ; as a necessary consequence, there- 

 fore, painting, like medicine, dwindles into froth and self-conceit, and 

 the pretended progress of science is but the apple-pip toxicology and 

 rabbit-squeaking physiology which disgraces the arts and paralyzes 

 the efforts of man ;" but to return. 



Abstract principles must bend to climate, to habit, and to prevailing 

 modes of manipulation to a certain degree. My own spirituous and 

 resinous vehicle has its defects; it does not sufficiently bear up, it 

 does not lay precisely where and as the touch is placed, pile on pile 

 does not lay to please many artists; I have, therefore, combined its 

 powers in oil alone, and believe, under the conditions above enume- 

 rated, it is as perfect as my experience can make it; and I have com- 

 bined it also in a substitute for McGelp; but, in taking my leave of 

 the Fine Arts for life, I cannot, among the conflicting wants and 

 wishes of artists, forget the Fable of the "Old Man and liis Ass," or, 

 that he who follows the maxim of Horace" is perhaps, during life at 

 least, as much respected after all as either the philosopher or the phi- 

 lanthropist. 



W. Marris Diksdale. 



May 1, 1845. 



' Let any man mix a little lake ^previously ground in turpentine and dry) with copal 

 varnish, and touch Mt on Hake white " in oil," when only ."half dry," this lake will 

 dry on the " wet surface" in four or five hours, and crack infallibly in three days— such is 

 the theory of Reynolds's miserable use of varnish, Venice turpentine, &c. &c. 



e 1 could fill a volume with proofs as strong as Holy Writ, and heartily wish success 

 to the College of Practical Chemistry, although I have some misgivings as to the practical 

 character ot its teachers, — where will you get them-'— The twaddle about Leibeg is be- 

 neath us. 



" Get place and wealth— if possible — with grace, 

 " If not— by any means— get wealth and place." 



ON THE INTRODUCTION OF CONSTRUCTIONS TO RE- 

 TAIN THE SIDES OF DEEP CUTTINGS IN CLAYS, 

 OR OTHER UNCERTAIN SOILS. 

 By Professor Hosking. 

 Paper read at the Institution of Civil Engineers, 



Deep cuttings are not only expensive, but their sloped sides are in 

 most soils so uncertain, anil subject to so many contingencies — in- 

 volving unforeseen outlay, as well as danger to the works, and inci- 

 dently to human life also; — that any mode of operation, which would 

 have the effect of rendering them more secure, though the original 

 expense were not reduced, would be deserving of consideration ; but 

 if it can be shown, that perfect security can be obtained at reduced 

 cost, the consideration becomes even more interesting. The expense 

 of the first formation of a cutting under given circumstances is easily 

 calculable, and so is the time within which the work may be efl>"cted. 

 Experience has proved that there is, for every soil, a limit in depth, 

 beyond which it becomes more expedient to drift the required way, 

 and construct an arched tunnel of sufficient dimensions, than to make 

 an open cutting with the requisite slopes. Even when the first cost 

 would not decide the question, the preference is nevertheless, often 

 given to the tunnel because of the greater security of constructed 

 work, than of the sides of au open cutting. There is, indeed, in prac- 

 tice, a considerable range, within which it has always been uncertain 

 whether — taking all things into consideration in each particular case — 

 tunnelling or open cutting is the fitter expedient and it is in this in- 

 termediate range, that something seems to be desirable, which has 

 not hitherto been practised. 



A tunnel, it may be remarked, is expensive, not from the nature 

 and extent of its construction, but from the circumstances in which 

 those constructions must be executed. The mere constructions are 

 less than would be consumed by common retaining walls to the sides 



