Niepce died while they were thus engaged. Daguerre prosecuted his researches alone, and toward the close of 1838 his success was such that he made known his invention to Arago, and Arago announced it in an eloquent and enthusiastic address to the French Academy of Sciences in January 1839. It at once excited great attention, which was heightened by the pictures produced by the new process. The French Government, in consideration of the details of the invention and its improvements being made public and on request of Daguerre, granted him an annuity and one also to Niepce's son.

At first only pictures of natural objects were taken; but in learning of Daguerre's process Dr. John William Draper of New York, a native of England and adopted son of America, the brilliant author of The Intellectual Development of Europe, and other great works, in the same year, 1839, took portraits of persons by photography, and he was the first to do this. Draper was also the first in America to reveal the wonders of the spectroscope; and he was first to show that each colour of the spectrum had its own peculiar chemical effect. This was in 1847.

The sun was now fairly harnessed in the service of man in the new great art of Photography. Natural philosophers, chemists, inventors, mechanics, all now pressed forward, and still press forward to improve the art, to establish new growths from the old art, and extend its domains. Those domains have the generic term of Photo-Processes. Daguerreotypy, while the father of them all, is now hardly practised as Daguerre practised it, and has become a small subordinate sub-division of the great class. Yet more faithful likenesses are not yet produced than by this now old process. Among the children of the

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; Photomicrography (to depict microscopic 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 object, 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, perfor ated 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 the 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