35S 



NATURE 



[Augtist 19, 1880 



d'Argent or silver white," " London and Nottingham 

 white," are both white lead, and therefore subject to the 

 same influences as " flake white." " Scheele's green," which 

 is an arsenite of copper, can hardly be called a " stable " 

 colour, "but unnecessar)'." 



" Semi-transparent colours." Amongst these is placed 

 " crcmintz white." Why this should be it is difficult to 

 understand, if flake white is to be ranked among per- 

 manent colours, for cremintz white is white lead produced 

 by precipitation. 



" Prussian blue" is spoken of as not being durable ; it 

 is quite certain that it stands well sometimes, but that its 

 hue does often fade. This must surely cause a reflecting 

 mind to ask himself how this can be ? The colour is so 

 beautiful and useful to the artist that some efibrt should 

 be made to prevent its total expulsion from his palette, 

 and here we have an instance of the importance of 

 chemical knowledge to the artist. It is impossible in this 

 place to go into the question ; it is however manifest if a 

 pigment stands well at one time but not at another that it 

 must be mixed, in the latter case, with something which 

 does not agree with it. Now this is true ; from its com- 

 position Prussian blue is affected by anything which will 

 change the state of oxidation in which part of its con- 

 stituent iron is held. Terra verte, for example, is, or 

 ought to be, an earth tinted with the protoxide of iron; if 

 this is mixed with prussian blue it will in time change the 

 condition of the oxide of iron in the prussian blue, and 

 therefore its colour. In concluding these remarks on 

 pigments treated of in Mr. Muckley's book one feels 

 great pleasure in being able to state that with the few 

 exceptions noticed there is nothing incorrect, only one 

 feels how terribly wanting it is in completeness when a 

 thoroughly scientific treatment of the subject is required. 

 One of the points which artists have to guard against is 

 adulteration of pigments ; now this is a thing of constant 

 occurrence, where cheap colours are bought, but in this 

 work nothing is said about this important matter. How- 

 ever well an artist may select his paints, impurities in one 

 or two of them may upset all his calculations and render 

 of no value a work which might, if sound, represent a 

 considerable sum of money. From the present position of 

 art in this country this is probably the most touching 

 way of putting it. It would be well, in a future edition 

 if Mr. Muckley would attend to this, and give some simple 

 methods by which the impurities could be detected. 



It is as important to the artist that he should under- 

 stand the nature of the vehicles with which he paints as 

 the composition of his pigments, and here one wishes 

 th.it Mr. Muckley had gone more into detail, and that he 

 had given reasons why such substances as maguilps, 

 mastic, sugar of lead, &c., are so very objectionable. The 

 reason why pictures crack is because two or more media 

 are used which dry differently; if the vehicle employed is 

 homogeneous there is no fear of cracking. Maguilp is 

 made by mixing linseed oil with mastic varnish, and 

 mastic varnish is gum mastic dissolved in turpentine. 

 When these are mixed together the turpentine goes to the 

 oil and leaves the mastic in a jelly-like condition ; the 

 whole mass is then rubbed up together, and in proportion 

 as the mixture is more or less complete so will the vehicle 

 be more or less liable 1 crack, because it is made up of 

 substances which take different times in drying. All 



maguilps are bad ; here Mr. Muckley is right, and he is 

 also right in advising the use of amber varnish and of 

 good copal varnish tempered with nut (better with poppy) 

 oil. No better media can be used than these, but the 

 picture must be painted from first to last with one of 

 them, whichever the artist selects, but the amber is the 

 best. Six years ago the then Professor of Chemistry at 

 the Royal Academy urged Messrs. Winsor and Newton 

 to get amber varnish made, and that firm did so, therefore 

 amber varnish has been to be had for that space of time, 

 and several artists of distinction, viz., Mr. Brett, Mr. 

 Vicat Cole, R.A., and others, have'painted with it to their 

 entire satisfaction ; nor have they complained that it is 

 too dark to mix with their lighter colours. When a 

 picture is perfectly hard which has been painted with this 

 vehicle, no better varnish can be used, when required; 

 than amber varnish properly applied, that is, in as thin a 

 coat as possible. Mr. Muckley speaks of mastic varnish 

 blooming, but he does not tell us why it does so. It is 

 because the substance is hygroscopic, and taking up 

 moisture is the cause of blooming, therefore it should 

 never be used. All driers, as he says, are unnecessary, 

 they are all ruinous to pictures ; under certain conditions 

 crystaUisable driers crystallise out and make the picture 

 spotty. It wovdd have been much more satisfactory if 

 Mr. Muckley had treated this part of his subject at greater 

 length and with greater minuteness ; it is evident that he 

 is quite competent to do so. Copal is a name used by 

 varnish makers for several kinds of gum, and some of the 

 cheap varnishes do not contain any of the better or harder 

 gura. The kind used for artists' varnishes is what is 

 termed a fossil gum, and is found largely at Zanzibar ; it 

 is almost, if not quite, as hard as amber, and almost 

 intractable. The best copal varnishes sold by the best 

 artist colourmen are, as a rule, made from this gum, and 

 can be obtained from them with confidence. It is how- 

 ever pleasing to learn that so conscientious and respectable 

 a firm as Messrs. Mander Brothers of Wolverhampton 

 have undertaken to manufacture vehicles " in accordance 

 with the old formulae supplied by the author." There is 

 no need whatever to use sandrac, it is very brittle and 

 unmanageable. 



In the work before us "turpentine" is spoken of as 

 being, in conjunction with colours, "detrimental to their 

 permanence." Turpentine, which is distilled with water 

 from coniferous trees, oxidises and forms a resin, this it 

 does most readily in the presence of moisture and sunlight 

 If then turpentine be kept free from moisture, in a well- 

 corked bottle, in the dark, this will not happen, and the 

 way to keep it free from moisture is to put into it lumps 

 of quicklime or fused chloride of calcium ; when so treated 

 it may be used with safety. One does not like to have so 

 old a friend banished without saying a word in his defence. 

 The suggestion made to use oil of lavender is a very good 

 one, but it need not displace turpentine, but both must 

 not be used together. 



"The conditions under which a painter commenced his 

 education in former times were totally different from what 

 they are now." It would be better for art if they were the 

 same, though perhaps not better for art regarded as a 

 trade. The paintings of the old masters certainly beat 

 most of the modern works in this country, both in merit 

 and durability. Mr. Muckley's remarks on this point are 



