Tube for Crystallizing Spermaceti.—Take a little capillary tube; curl one of its ends into a ring, and solder the other to a cylindrical reservoir, two-thirds of the capacity of which you fill with very pure spermaceti dissolved in sulphuric ether; you then seal the point of the reservoir. See [pl. 3], fig. 27.
Tube for demonstrating the non-conductability of Heat by Liquids.—This is represented by [pl. 2], fig. 26. It is a tube sealed at one end, bordered at the other, and bent in such a manner as conveniently to permit the upper part of a column of liquid to be exposed to heat.
Tube for estimating the Density of Vapours.—Represented by [pl. 2], fig. 14. It is merely a tube sealed at one end, bordered at the other, and bent as shewn by the figure.
Tubes for exposing Substances to Heat and Gases.—This instrument consists of a tube bent in the middle into a U. [Pl. 3], fig. 3. It is much employed in chemistry, for containing substances which we wish at the same time to expose to an elevated temperature and to the action of certain gases. This tube can also be employed for cooling gases, or liquids, in distillation; the bent part being, in this case, dipped into water or a freezing mixture, or enveloped in wet paper or cloth.
Tubes for the Preservation of Objects of Natural History, or of Chemical Preparations.—Take a tube of which the width and length corresponds with the object which is to be enclosed; draw it out at one end, and, after having obstructed the point, twist it into a ring. Introduce the object by the open extremity, which you must afterwards draw out; fill the tube with the liquid necessary to preserve the object, and then seal the point. See [pl. 2], fig. 27.
If you desire to have the power of taking out the object at will—as, for example, when grain is preserved, or when, in chemistry, the tube is employed to contain salts and other compounds, of which small quantities are now and then required for use—you do not seal the end of the receiver, but border it in such a manner that it can be closed by a cork.