276 



NATURE 



[November 12, 1914 



are not exclusive ; for there are many things in 

 their methods which we might with advantage 

 copy ; and we could perhaps boycott trade con- 

 ducted according to plans which we consider dis- 

 honourable or underhand. Time alone will show. 

 But this is a fitting opportunity to consider our 

 position ; and by organisation, by co-operation 

 among our manufacturers rather than by com- 

 petition between them, and by education in science 

 of our directors and employees, we might do 

 much to forestall the attack which will undoubtedly 

 again be made on our commercial position, if, at 

 the end of the war, any prospect of recuperation 

 is left to Germany. William Ramsay. 



SCIENCE THE HANDMAID OF ART. 

 The Pigments and Mediums of the Old Masters. 

 By Prof. A. P. Laurie. Pp. xiv + 192 + xxxiv 

 plates. (London: Macmillan and Co., Ltd., 

 1913.) Price 8s. 6d. net. 



THE information given in this book shows 

 that the scientific man has come to the aid 

 of the art expert in his endeavour to determine 

 the period and the authorship of paintings of dis- 

 puted origin. The author's previous works on 

 " Greek and Roman Methods of Painting " and on 

 " Materials of the Painter's Craft " indicate in 

 what degree historical and literary research 

 coupled with technical knowledge can be relied 

 upon as guides in such an inquiry. 



The present volume shows to what extent exact 

 experimental investigation can be utilised to assist 

 in this matter. The methods available are based 

 upon an examination of the physical and chemical 

 properties of the pigments and mediums used, and 

 a microscopical examination of the nature of the 

 brush work of the picture. The latter has given 

 very interesting results, and shows that great 

 individuality is found in the work of different 

 artists. 



The method recommended by the author for a 

 critical examination of the brush work is to make 

 a photomicrographic reproduction of a selected 

 portion of the picture under a magnification of 

 about three diameters. 



The author is gradually accumulating a series 

 of such photomicrographs, of well-authenticated 

 pictures, and these will certainly be a valuable 

 aid in the detection of forgeries, copies, etc. Some 

 striking plates are shown in the book illustrating 

 the use of such brush work enlargements, and 

 the value of the method is well seen by a com- 

 parison of plates vi. and vii.- — the former from a 

 picture by J. A. Watteau and the latter from a 

 copy by a good modern artist. 



In addition to their use for the purpose of 

 NO. 2350, VOL. 94] 



identification, it appears probable that such photo- 

 micrographs might be of much value for instruc- 

 tional purposes, as indicating the methods adopted 

 by noted artists in developing their effects. 



The first ten chapters of the book deal with 

 the examination of the pigments and mediums. 

 The physical character of the pigments, such as 

 coarseness of particles, simple or mixed character, 

 etc., may be frequently determined in situ under 

 a magnification of about 100 diameters; but the 

 removal of a minute fragment of pigment for more 

 detailed examination is usually desirable. This 

 may be done by making use of a microscopic gouge 

 about a millimetre in diameter, or a complete 

 section through the picture may be obtained by 

 using a hypodermic needle. Full instructions are 

 given for the transference and examination of the 

 fragments of pigment, all tests, of course, being 

 applied under the microscope. 



The identification of the pigments and medium 

 used in well authenticated pictures, coupled with 

 historical information regarding the nature of the 

 pigments in use at certain periods, makes it pos- 

 sible approximately to date many pictures, and 

 the knowledge of the particular palette used by 

 an artist, together with an examination of his 

 brushwork, greatly facilitates a judgment in cases 

 of doubtful authenticity. 



The book is thus of much interest, not only to 

 dealer and collector, but to the artist and historian. 

 It is obvious, however, that the new methods of 

 examination should be applied to valuable works 

 of art only by such special experts as Prof. 

 Laurie, and there is some slight danger involved 

 in the publication of methods of sampling "old 

 masters," even when the sample is to be taken 

 with a hypodermic needle. 



Walter M. Gardner. 



PUBLIC HEALTH. 

 (i) Preliminary Report on the Treatment of Pul- 

 monary Tuberculosis with Tuberculin. By Dr. 

 Noel D. Bardswell. With a Prefatory Note 

 by Prof. Karl Pearson. Pp. xxi+141. (London: 

 H. K. Lewis, 1914.) Price 65. net. 



(2) Cambridge Public Health Series. Isolation 

 Hospitals. By Dr. H. Franklin Parsons. 

 Pp. xiv + 275. (Cambridge : University Press, 

 1914.) Price 125. 6d. net. 



(3) The Bacteriological Examination of Food and 

 Water. By Dr. William G. Savage. Pp. x+ 

 173. (Cambridge : L^niversity Press, 1914-) 

 Price 75. 6d. net. 



(i) T^REATMENT of tuberculosis, and in par- 



X ticular pulmonary tuberculosis (phthisis 



or consumption), with tuberculin is undoubtedly 



i tending to increase in England, and a number of 



