Ship building is hastened by these same air drilling and riveting machines. The propelling of cars, road vehicles, boats, balloons, and even ships, by explosive gases and compressed air is an extensive art in itself, yet still in its infancy, and will be more fully described in the chapter on carrying machines. The realm of Art has received a notable advancement by the use of a little blow-pipe or atomiser by which the pigments forming the background on beautiful vases are blown with just that graduated force desired by the operator to produce the most exquisitely smooth and blended effects, while the varying colours are made to melt imperceptibly into one another as delicately as the mingled shade and coloured sunlight fall on a forest brook. But to enumerate the industrial arts to which air and other pneumatic machines have been adapted would be to catalogue them all. Mention is made of others in chapters in which those special arts are treated. CHAPTER XIII. ART OF HEATING, VENTILATING, COOKING, REFRIGERATION AND LIGHTING. That Prometheus stole fire from heaven to give it to man is perhaps as authentic an account of the invention of fire as has been given. It is also reported that he brought it to earth in a hollow tube. If a small stick or twig had then been dipped into the divine fire the suggestion of the modern match may be supposed to have been made. But men went on to reproduce the fire in the old way by rubbing pieces of wood together, or using the flint, the steel and the tinder until 1680, when Godfrey Hanckwitz of London, learning of the recent discovery of phosphorus and its nature, and inspired by the Promethean idea, wrapped the phosphorus in folds of brown paper, rubbed it until it took fire, and then ignited thereat one end of a stick which he had dipped in sulphur; and this is commonly known as the first invented match. There followed the production of a somewhat different form of match, sticks first dipped in sulphur, and then in a composition of chlorate potash, sulphur, colophony, gum of sugar, and cinnabar for coloring. These were arranged in boxes, and were accompanied by a vial containing sulphuric acid, into which the match was dipped and thereby instantly ignited. These were called chemical matches and were sold at first for the high price of fifteen shillings a box. They were too costly for common use, and so our fathers went on to the nineteenth century using the flint, the steel and the tinder, and depending on the coal kept alive upon their own or their neighbour’s hearth. Prometheus, however, did reappear about 1820-25, when a match bearing the name “Promethean” was invented. It consisted of a roll of paper treated with sugar and chlorate of potash and a small cell containing sulphuric acid. This cell was broken by a pair of pliers and the acid ignited the composition by contact therewith.