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 safe-makers. 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.