Oct., 1890. 
PAINTING SLIDES FOK THE MICROSCOPE. 
229 
on very thick, but do not pass over the outline. Dry this, 
and when it is quite dry pour water over the slide, or move 
the slide up and down in a basin of clean water. All the 
blue will come off, leaving a light stain, which is just sky 
colour. The clouds can be picked out of this with a brush as 
the slide slowly dries. You will then have a sky without a 
brush mark. Cloudy skies, such as a sunset, require more 
care, and you cannot do them this way. No colour that I 
know of, except Prussian blue, will act so, and not every 
sample of Prussian blue. But this, I have since found, is not 
so good a way as painting the sky the right tint, and then 
softening. it by breathing on it and using a soft brush. 
Slides of this kind are varnished in the same way 
as the scientific slides, but if on trying them on the screen 
you find any parts that need to be darkened you can 
paint over the slide (when the varnish is dry) where 
it needs it, and it is better not to varnish it again. I have 
tried this re-enforcing business with oil paint. It is not at all 
a success, and water colours are far better than oils for paint¬ 
ing lantern slides, because vou can make much finer lines. 
My friends, when they see my slides on the screen for the 
first time, always say, “I shouldn’t have thought it possible 
to paint as finely as that, the working hardly looks coarse at 
all.” Nor does it. At the distance of a few feet you do not 
observe that the picture is not as highly finished as it would 
be if painted the size of the image on the screen. 
Figures and landscapes may be copied, if small enough, by 
placing the ground glass over the picture and so tracing the 
outline. But, unfortunately, this is seldom the case. So I 
have my piece of card ruled with T 3 g squares, on which is also 
a circle three inches across. I then have four or five pieces of 
tracing paper of different sizes, but all ruled with the same 
numbei of squares as my card, and also similarly inscribed with 
circles. Finding by experiment the right sized piece of paper, 
it is not difficult to copy the picture on a reduced scale, by 
means of the guidance afforded by the small squares, which of 
course are rather larger in the large circle than in the small 
one. The tracing paper is laid on the picture, and kept flat 
by a piece of glass. The painting is the same as in the case 
of scientific diagrams. I have now painted nearly 300 of 
these slides of pictures, and they are highly popular with 
children—of all ages. My friends frequently say, “ When you 
are going to show your slides again to some children I wish 
you would ask me.” Of course it is of no use to try, if you 
cannot draw, but, if you can, you will be very pleased with 
the result. 
