WHAT, one wonders, would Caxton with his simple printing press have made, for instance, of the great rotary presses that pour out into the world their millions of papers daily ? At the International Printing Exhibition, to bo held at Olympia this month, every branch of printing will be represented, including almost every kind of type from all countries. Special attention will be paid to publicity printing, such as posters, leaflets, etc. The last International Exhibition was held four years ago, but improvements have been so vast since then that the present exhibition, with its working models, will in no way cover the same ground. The interest in the International Printing Exhibition at Olympia is therefore not merely to the trade ; it is equally interesting to the public at large. Lord Riddell, the great newspaper proprietor and publisher, is eminently the person to introduce such an exhibition to the listener.