April 2^, 1878 



NATURE 



517 



material with more precautions. Others, again, and among 

 them Sir Joshua Reynolds, have in their different works followed 

 various practices, and consequently had varied results. Thus, 

 some of Sir Joshua's pictures have kept perfectly sound. Others 

 are cracked in the characteristic way just mentioned. Others, 

 again, are cracked in an absolutely irregular way. We can 

 easily form an idea of it if we read in his "Diary Notes," for 

 instance, the way in which he painted the portrait of Miss 

 Kirkman, which he began with whiting and gum tragacanth, 

 then covered it successively with wax, then white of eggs, and 

 then varnished it. 



The study of the alterations already fully developed in pictures 

 painted within the last hundred years only, and their comparison 

 with the works of the old masters, would suggest the following 

 rules for the process of painting : — 



1 . The oil should in all colours be reduced to a minimum, and 

 under no form should more of it than absolutely necessary be 

 introduced into a picture. 



2. All transparent colours which dry very slowly should be 

 ground, not with oil at all, but with a resinous vehicle. 



3. No colour should be put on any part of a picture which is 

 not yet perfectly dry; and, above all, never a quick -drying 

 colour upon a slow-drying one, which is not yet perfectly 

 dry. 



4. White and other quick-drying opaque colours may be put 

 on thickly. On the contrary, transparent and slow-drying 

 colours should always be put on in thin layers. 



If the effect of a thick layer of these latter is required, it 

 mu-t be produced by laying one thin layer over another, taking 

 care to have one completely dry before the next is laid on. If 

 transparent colours are mixed with sufficient quantity of white- 

 lead, they may be treated like opaque ones. 



We come now to the last layer of the picture, to that one 

 which is spread over its surface in order to equalise optical 

 irregularities, and to protect it at the same time from the air. 

 I mean the varnish. 



The varnish may crack or get dim ; then it should be treated 

 with Pettenkofer's method ; but it may become dark yellow, 

 brown and dirty, and so hide the picture that it becomes neces- 

 sary to take it off and to replace it by a thin layer of new var- 

 nish. It is here that picture-restorers, or we may say picture- 

 cleaners, display their beneficial skill, and also their very 

 destructive activity. 



If a picture is throughout painted in oil, if its substance has 

 remained sound and even, and varnished with an easily soluble 

 mastich or dammar varnish, then there will be neither difficulty 

 nor danger in removing the varnish. This can, in such a case, 

 be done either by a dry process, that is, by rubbing the surface with 

 the tips of the fingers, and thus reducing the varnish by degrees to a 

 fine dust, or by dissolving the varnish by application of liquids, 

 which, when brought only for a short time into contact with the oil 

 painting, will not endanger it. We have, however, seen that the 

 works of the old masters are not painted with oil colours like those 

 used by modern painters, but, on the contrary, that certain 

 pigments, and especially the transparent colours used for glazing, 

 were gi-ound only with resinous substances. These latter have, 

 in the course of time, been so thoroughly united with the 

 layer of varnish spread over the surface of the picture, that 

 there no longer exists any decided limit between the picture and 

 the varni;h. It is in such pictures that a great amount of 

 experience, and knowledge of the process used for the picture, 

 as well as precaution, are required in order to take away from 

 the varnish as much only as is indispensable, and without inter- 

 fering with the picture itself. Numberless works of art have 

 been irreparably injured by restorers, who, in their eagerness to 

 remove dirt and varnish, attacked the painting itself. They 

 then destroyed just that last finishing touch of the painting, 

 without which it is no longer a masterpiece. 



The difficulty and danger are much greater in cleaning those 

 pictures which have not been varnished with the ordinary easily- 

 dissolved mastich or dammar varnish, but have been painted 

 over with oil, oil-varnish, or oleo-resinous varnish. It seems 

 incredible that these substances should ever be used for such 

 purposes ; it is, however, a fact that there are still people who 

 fancy that it will contribute to the good preservation of their 

 pictures to brush from time to time a little of those liquids over 

 their surface. They recognise too late that the varnish becomes 

 more and more dark, of a brownish colour, and opaque. If 

 such varnish has afterwards to be removed, then we meet with 

 the great difficulty, that this can be done only with substances 



which would just as easily dissolve the whole picture as the 

 hardened layers spread over it. 



ITiis shows what can be the value of those univers^al remedies 

 which from time to time appear, and are praised for the inno- 

 cuous way in which pictures by their means may be cleaned. 



There is at this moment a great discussion going on in Italy 

 about Luporini's method. Luporini is a painter and picture- 

 restorer in Pisa, who believes himself to have invented a new 

 means of cleaning pictures without any danger. Some months 

 ago, in Florence, I examined a large number of pictures cleaned 

 by him. Those of the Gallery of St. Donato, belonging to 

 Prince Demidoif, mostly Flemish and Dutch landscapes, are 

 cleaned vei7 well and without any injury to the painting. On 

 the contrary, the St. John, by Andrea del Sarto, one of the 

 finest pictures of the Palazzo Pitti, I found very much altered 

 by the restoration of Luporini. I had studied that picture very 

 closely the year before, and should now sooner believe it to be a 

 modern copy than the cleaned original. It has lost all softness 

 of outline and the characteristic expression of the face. The 

 change in the flesh tints can scarcely be explained otherwise but 

 by an entire removal of the glazing. 



I think it is taking a heavy responsibility to allow a new 

 experiment to be tried upon such an invaluable work of art. 

 Even private person-, who are fortunate enough to be in possess- 

 sion of such treasures, ought to feel responsible for the good 

 preservation of masterpieces, which are, it is true, their material 

 property, but which intellectually belong to the whole civilised 

 world of the present and of the future. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



Cambridge.— Messrs. Mackren, Robbs, and Hichens, have 

 been appointed to Scholarships in Natural Science at Gonville 

 and Caius College. 



Edinburgh. — At the Graduation Ceremonial on Tuesday 

 the degree of Doctor of Science in the Department of Mental 

 Science, was conferred on Jacob Gould Schurman, B.A. ; in 

 the Department of Mathematics on Alexander Macfarlane, M.A., 

 B.Sc. ; in the Department of Chemistry on William Inglis 

 Clark, B.Sc. The degree of Bachelor of Science was conferred 

 on William Thomson in the Department of the Mathematical 

 Sciences ; on John Adrian Blaikie and James Johnstone Dobbie in 

 the Department of the Physical Experimental Sciences ; on 

 William A. Haswell in the Department of the Natural Sciences ; 

 on James Alfred Ewing and John Gray in the Department of 

 Engineering ; and on John Brown, M.D., John Berry Ilaycraft, 

 M.B., CM., and John Trehame, M.B., CM., in the Department 

 of Public Health. The Hope Prize Scholarship in Chemistry 

 was awarded to Mr. Lewis Johnstone, and the Falconer Memorial 

 Fellowship for the encouragement of the study of Palaeontology 

 and Geology, of the annual value of 100/., tenable for two 

 years, and conditionally for four years, was awarded to R, A. 

 Lundie, M.A., B.Sc. 



Baltimore. — We recently referred to the system of fellow- 

 ships at the Johns Hopkins University, Baltimore. P>om a 

 statement on the subject which has come to hand, we learn that 

 twenty fellowships, each yielding 500 dols. a year, are annually 

 open in the University. They are awarded by the trustees on 

 the nomination of the Faculty, as nearly on the first of -June as 

 may be found practicable. Candidates are invited from any part 

 of the country. The object of this foundation is to give to a 

 few scholars of promise the opportunity to prosecute further 

 studies, under favourable circumstances, and likewise to open a 

 career for those who propose to follow scientific and literary 

 callings. The University expects to be benefited by the presence 

 and influence of the Fellows, and by their occasional services ; 

 from among the number it hopes to secure from time to time 

 some of its teachers. Three of the twenty fellowships are 

 allotted this year to each of the five departments, Greek, mathe- 

 matics, chemistry, physics, and biology ; and the remaining five 

 will be allotted either in these departments or in others, at the 

 discretion of the Faculty. Appointments are made by a careful 

 consideration of all the evidence submitted to the Faculty, 

 Every candidate in presenting his name is expected to address a 

 letter to the president indicating the course of his previous 

 reading and study, and his general purposes with reference to 

 future work. It is desirable for him to present in printing or 

 manuscript an essay or thesis which may have been written either 



