Photo-Process family are the Calotype, Ambrotype, Ferreotype, Collodion and Silver Printing, Carbon Printing, Heliotype, Heliogravure, Photoengraving (relief intaglio-Woodburytype), Photolithography; Alberttype; Photozincograph, Photogelatine-printing; Photomicography (to depict microsocopic objects), Kinetographs and Photosculpture. A world of mechanical contrivances have been invented:Octnometers, Baths, Burnishing tools, Cameras and Camera stands, Magazine and Roll holders; Dark rooms and Focussing devices, Heaters and Driers; Exposure Meters, etc. etc.

The Kinetograph, for taking a series of pictures of rapidly moving objects, and by which the living ob ject, person or persons, are made to appear moving before us as they moved when the picture was taken, is a marvellous invention; and yet simple when the process is understood. Photography and printing have combined to revolutionise the art of illustration. Exact copies of an original, whether of a painting or a photograph, are now produced on paper with all the original shades and colours. The longsought-for problem of photographing in colours has in a measure been solved. The "three colour processes" is the name given to the new offspring of the inventors which reproduces by the camera the natural colours of objects.

The scientists Maxwell Young and Helmholtz established the theory that the three colours, red green, and blue, were the primary colours, and from a mixture of these, secondary colours are produced. Henry Collen in 1865 laid down the lines on which the practical reduction should take place; and within the last decade F. E. Ives of Philadelphia has invented the Photochromoscope for producing pictures

in their natural colours. The process consists in blending in one picture the separate photographic views taken on separate negative plates, each sensitised to receive one of the primary colours, which are then exposed and blended simultaneously in a triple

camera.

Plates and films and many other articles and processes have helped to establish the Art of Photography on its new basis.

Among the minor inventions relating to Art, mention may be made of that very useful article the lead pencil, which all have employed so much time in sharpening to the detriment of time and clean hands. Within a decade, pencils in which the lead or crayon is covered instead of with wood, with slitted, perforated or creased paper, spirally rolled thereon, and on which by unrolling a portion at a time a new point is exposed; or that other style in which a number of short, sharpened marking leads, or crayons, are arranged in series and adapted to be projected one after the other as fast as worn away.

In Painting modern inventions and discoveries have simply added to the instrumentalities of genius but have created no royal road to the art made glorious by Titian and Raphael. It has given to the artists, through its chemists, a world of new colours, and through its mechanics new and convenient appliances.

Air Brushes have proved a great help by which the paint or other colouring matter is sprayed in heavy, light, or almost invisible showers to produce backgrounds by the force of air blown upon the pigments held in drops at the end of a fine spraying tube. Made of larger proportions, this brush has been used for fresco painting, and for painting large objects,

such as buildings, which it admits of doing with great rapidity.

A description of modern methods of applying colours to porcelain and pottery is given in the chapter treating of those subjects.

Telegraphic pictures:-Perhaps it is appropriate in closing this chapter that reference be made to that process by which the likeness of the distant reader may be taken telegraphically. A picture in relief is first made by the swelled gelatine or other process; a tracing point is then moved in the lines across the undulating surface of the pictures, and the movements of this tracer are imparted by suitable electrical apparatus to a cutter or engraving tool at the opposite end of the line and there reproduced upon a suitable substance.

CHAPTER XXVII.

SAFES AND LOCKS.

PRIOR to the century safes were not constructed to withstand the test of intense heat. Efforts were numerous, however, to render them safe against the entrance of thieves, but the ingenuity of the thieves advanced more rapidly than the ingenuity of safemakers. And the race between these two classes of inventors still continues. For with the exercise of a vast amount of ingenuity in intricate locks, aided by all the advancement of science as to the nature of metals, their tough manufacture and their resistance to explosives, thieves still manage to break in and steal. The only sure protection against burglars at the close of this nineteenth century appears to consist of what it was at the close of any previous century-the preponderance of physical force and the best weapons. Among the latest inventions are electrical connections with the safe, whereby tampering therewith alarms one or more watchmen at a near station.

A classification of safes embraces, Fire-proof Burglar-proof, Safe Bolt Works, Express and Deposit Safes and Boxes, Circular Doors, Pressure Mechanism, and Water and Air Protective Devices.

The attention of the earliest inventors of the century were directed toward making safes fire-proof, In England the first patent granted for a fire-proof safe was to Richard Scott in 1801. It had two cas

ings, an inner and outer one, including the door, and the interspace was filled in with charcoal, or wood, and treated with a solution of alkaline salt.

This idea of interspacing filled in with non-combustible material has been generally followed ever since. The particular inventions in that line consist in the discovery and appliance of new lining materials, variations in the form of the interspacing, and new methods in the construction of the casings, and the selection of the best metals for such construction.

In 1834 William Marr of England patented a lining for a double metallic chest, filled with noncombustible materials such as mica, or tale clay, lime, and graphite. Asbestus commenced to be used about the same time.

The great fire in New York City in 1835, destroying hundreds of millions of dollars' worth of property of every description, gave a great impetus to the invention of fire-proof safes in America.

B. G. Wilder there patented in 1843 his celebrated safe, now extensively used throughout the world. It consisted of a double box of wrought-iron plates strengthened at the edges with bar iron, with a bar across the middle; and as a filling for the interspaces he used hydrated gypsum, hydraulic cement, plaster of paris, steatite, alum, and the dried residuum of soda water.

Herring was another American who invented celebrated safes, made with a boiler-iron exterior, a hardened steel inner safe, with the interior filled with a casting of franklinite around rods of soft steel. Thus the earth, air and water were ransacked for lining materials, in some cases more for the purpose of obtaining a patent than to accom