J. G. QoodcMld — Koio to talie Impressions of Fossils. 207 



gutta percha, etc., are apt to do ; consequently when the tinfoil is 

 ■withdrawn it never drags away part of the fossil. "When the foil is 

 loosened so that it will lift off easily, it should be gently pressed 

 back again with the brush so as to make it resume its proper shape. 

 Then, if the subject is tolerably flat, and no holes have been torn in 

 the foil, it may be lifted off at once. To fix it, the most important 

 part of the process, it will generally suffice to pour on to the 

 impressed, or under, side, sufficient shellac varnish (which should 

 be of a consistence between that of cream and that of treacle) to 

 float the whole surface. This should not be distributed by means of 

 a brush, but by simply turning the impression about until the surface 

 is covered by the varnish. In a few minutes this will be dry enough 

 to lay by. A second coating, later on, will render it quite hard 

 enough to stand ordinary handling without any risk of altering its 

 shape. 



Should the fossil be in somewhat higher relief, so that a few holes 

 are torn in the foil, the best mode of treatment is to go over the 

 upper surface of the " counterfeit " with a thin coat of melted 

 paraflfine while it is on the original. The wax chills at once into 

 a firm mass, and the foil may be lifted off with ease. Then the 

 back is floated with varnish as before. When this is set, all that 

 is necessary to do is to put the foil into water sufiiciently hot to 

 melt the paraffine, which at once floats off, leaving the foil quite 

 bright, as before. 



In the case of objects in very high relief more care is, of course, 

 required ; but the process answers very well even then. Thanks to 

 the courtesy of Dr. Traquair, I have been enabled to make tinfoil 

 counterfeits of a large number of fossils from the collection in the 

 Edinburgh Museum of Science and Art, many of them in high relief, 

 by this process ; and, with a little management, have been able to 

 make them retain the form of the original perfectly, by coating the 

 inside of the impression with cotton-wool, and flooding this with 

 varnish as before. 



In some respects impressions made by this process are even better 

 than the originals ; for the metallic lustre of the tinfoil causes the 

 light to be reflected from the salient parts of the copies much more 

 strongly than from the originals. Indeed, when the part of the foil 

 representing the matrix is painted a dead black, I find it much 

 easier to draw from the foil impressions than from the originals. 



Another advantage presented by this method is that any number 

 of copies can be made in a very short space of time ; and in lecturing 

 on Palaeontology in Edinburgh, I am able in the majority of cases 

 to place in the hands of each student a reliable copy of the fossil 

 I am describing, and in this way he is able to make more satisfactory 

 progress than would otherwise be possible. 



Lastly, as Curator of a Collection embracing nearly twenty 

 thousand specimens of fossils, I am occasionally called upon to lend 

 out specimens for description. In all such cases my plan is to take 

 a careful tinfoil counterfeit of the original before it goes out, and 

 this, with the register entry, places the exact nature of the loan on 

 record in a manner that leaves nothing to be desired. 



