this triangle the colors of Newton's rings would fall. Lord Rayleigh, by
means of a diagram and the selenite wedge, showed that the relations to the
three standard colors in practice were identical with the position assigned
them by theory.

In conclusion, the lecturer showed a piece of glass, the surface of which
had been decomposed, a ray of light transmitted through which showed upon
the screen patches of very pure color. These he considered to be due to the
glass consisting of a number of thin plates, some of which had been removed
by the decomposition.

* * * * *




BELT JOINTS.


From time to time, serious accidents have taken place, and the progress of
work stopped, by the sudden snapping of driving belts in machinery, and, as
a general rule, it is found that the collapse is attributable either to
faulty leather or insecure joining. A great improvement of the leather
intended for belts has been brought about during the last few years, by the
introduction of improved processes for currying and the subsequent
treatment. Paterson has worked successfully a patent for rendering belt
leather more pliable, and lessening the tendency to stretch. Under this
treatment the leather is either curried or rough dried, and then soaked in
a solution of wood, resin, and gum thus, or frankincense, first melted
together, and then dissolved, by the application of heat, in boiled or