He should also practise using the blowpipe until he can keep up a steady and uninterrupted flame for ten minutes or a quarter of an hour, without stopping for breath. It is quite possible to replenish wind in the mouth, which alone ought to be used, without interrupting the breathing for an instant, but it requires some practice.
(1) Box blowpipe, A, the stem; B, the mouthpiece; C, the box, in which is placed a piece of sponge to absorb the moisture of the breath; D, the extremity (this is moveable, and each blowpipe has several, with different apertures); E, the hollow pivot, in which the extremity and its arm turn. The box is opened by the milled ring seen at the bottom.
SPECTRUM ANALYSIS.
If the youthful student wishes to occupy his leisure in a most amusing and instructive manner, and at the same time to acquire a ready method of testing for the presence of the various metals, he cannot do better than purchase from Mr. John Browning, of 111, Minories, the Amateur’s Spectroscope, price two guineas; or, if sufficiently ingenious, a prism and lenses may be purchased for sixteen shillings, and fitted up in paper tubes. Indeed, it is always better to buy some complete set or portion of a set of apparatus, instead of the trashy so-called “Boys’ Cabinets,” which contain very much that is useless and very little for instructive experiments. The instrument enables the observer to examine the properties of metallic salts when in the state of a glowing or incandescent gas. Common light affords a continuous spectrum or band of colours, red at one end and violet at the other, the intermediate colours being orange, yellow, green, blue, and indigo. The spectra of the metals in the state of luminous vapour are not continuous, but are represented by distinct bands or lines of light.
Solar Spectrum, and Spectra of the Alkanes and Alkaline Earths. Copied from the Original Drawings of G. Kirchhoff and R. Bunsen.
 | |
| Ka | |
| Na | |
| Li | |
| Sr | |
| Ca | |
| Ba | |
| Spectrum of the Metal discovered by Professor Bunsen. |