DECORATIVE NATURAL HISTORY WORK. 117 



thing with strong silvery reflections a roach or dace, 

 for instance. For certain kinds of beetle a blue trans- 

 parency, backed with a " blued " metal, approximates 

 very closely indeed to nature's colouring. The writer 

 inclines to the use of thin sheets of copper, silvered, if 

 desirable, as a metallic backing. The simplest way to 

 mount them in contact is as follows. Select a printing 

 frame a size larger than the picture, say a whole-plate 

 one for a half-plate transparency. Make a stout cut-out 

 mount, and cement the edges of the transparency to 

 the back of it. Bend your sheet of metal so that it 

 curves from the centre to opposite ends. Place the 

 convex side gently on the transparency, and clamp the 

 back of the printing frame gently down. Experiments 

 with aluminium as a backing have led the writer to the 

 conclusion that it is useless until the trade devise some 

 more reliable means of " frosting " the surface. He has 

 been given to understand that the process of frosting is a 

 difficult one, and the samples he has been supplied 

 with have certainly not been satisfactory. This is the 

 more unfortunate, as the white and non-tarnishable 

 quality of the metal would render a good preparation of 

 it particularly useful. 



As a "general rule, a " frosted " or " matt " metal 

 surface will be found more desirable than a highly 

 polished one. Small scratches thereon are of less 

 consequence ; and the shadows of the transparency 

 are more brightly illuminated when viewed at other 

 than one particular angle. Opal is well suited to 

 soft furry subjects mice, for instance, or moths ; the 



