Page:An Encyclopædia of Cottage, Farm, and Villa Architecture and Furniture.djvu/1047

 FITTINGS-UP OF VILLA OFFICES. I 023 2044. Mallet's Apparatus for Cooking hy Gas Flame. " Annexed you have two or three figures (figs. 1825 to 1829) of my ideas for cooking by gas flame; a thing which has long floated in my head, but which I have said nothing of, lest the folks should suppose me ' daft, ' as they say in your country. Some iew years ago, I had occasion to make some weldings of iron where it was an important object that the metal should not be burnt away in the fire; and for this purpose I endeavoured to use a kind of hu<re gas blowpipe. I got one made of the kind shown in fig. 1825 as far as each jet is con- cerned, but of a much larger size. In this figure, a is the air tube ; b, is the gas tube ; c, the gas cock ; and d, an end view of the point of the blowpipe, in which e is the circular orifice for the emission of air, and /that for the emission of gas. Mr. Daniell, of King's College, London, has since published the same thing as new, and of his invention • however, I can establish priority by my laboratory journal. To proceed : the jet, or blowpipe, is so made, that a current of atmospheric air is forced into the centre of the o-as flame, by which means the latter is converted into a blowpipe of great power. Instead of a mere circle of gas-burners, I use a certain number of such blowpipe flames, arranged as radii of a circle, as in fig. 1826, in which g is the air pipe, and h the gas pipe; and each of the branches to the jets from these pipes has four small collars of leather or stuffing boxes, so that any one can be approached to, or withdrawn from, the centre of the circle, or raised or lowered, as occasion may require. Fig. 1827 is a sectional view of such an apparatus complete, in action ; a circular main tube, /, supplies the gas to all ; and another, h, supplies the current of air, the means for producing which I will describe hereafter. The article to be roasted, /, is suspended from a bottle-jack, but with a swivel (such as those used by anglers) interposed ; so that it may be permitted to turn, or be stopped, the jack still going on, as may be required. Above and below it are parabolic plated copper reflectors, mm ; the lower one with a receptacle for dripping, n ; and the upper one with six or eight small discs of plate glass, o o, inserted in proper places, to enable the operator to view the progress of coc- tion. Each burner has a copper cone, p, placed so as to slide over it ; by which means, besides the radiated^ heat convergent on the roasting matter, a current of hot air is con- tinually urged against it, as shown more fully in fig. 1828. The upper reflector is hung by balance weights, so as to throw up in a moment; and, besides a cock to each individual gas tube of each burner, there is a general one to each of the air and gas main-tubes, so as to diminish the heat generally, or in any particular spot.