268

VENTILATION.

TURPENTINE, SPIRITS, ESSENCE, OR OIL OF. Camphen is the newname given by the continental chemists to every ethereons or volatile oil, which is com-posed of 5 atoms of carbon and 8 of hydrogen, and which combines directly with hydro-chloric acid, either into a solid or a liquid compound, resembling camphor. Under thistitle the following oils are included: turpentine, citron, or lemon, orange-flower,copaiva, balsam-oil, juniper, cubebs, and pepper. Some add to this last—the oils ofcloves, valerian, and bergamot. As the new patent lamps burn spirits of turpentine,they have been called Camphine. (See Lamps.) Since that article was printed I havehad occasion to test a variety of Camphine lamps during the preceding three months, andI am convinced the patent Vesta lamp of Mr. Young is not merely the best, but it is theonly one hitherto made public, which can be used with comfort in closed apartments.It was the first spirit lamp constructed on right principles, keeping in view the peculiarnature of Camphine spirits, and being secured by a correct specification, leaves no roomto expect another equally good. In this lamp the burner is completely insulated fromthe reservoir by a ring of wood, or other non-conducting material, placed between them,and as no metallic tube passes down from the flame into the volatile spirits, they remaincold; whereas, when such a tube passes down through the reservoir, for the admissionof air to the inside of the flame (as in all other argand lamps), without being insulatedfrom the flame, the spirits become 20 or 30 degrees hotter, so as to emit acrid andofl'ensive fumes. The wick also, which embraces the heated tube becomes dry andresinous, loses its capillary power, coals at the flame, and then sends up smoke with ashower of lamp black.

The Vesta lamp is free from these defects, and when used with properly rectifiedspirits, never smokes nor smells; it may be easily distinguished by the above characters,and by the circumstance of the air passing between the wicks to the interior of theflame. It affords, undoubtedly, the brightest, cleanliest, and most economical light,hitherto invented, when supplied with pure spirits free from rosin. I have lighted mydrawing-rooms with the Vesta lamp for several evenings successively, without havingits wick trimmed or its occasioning the slightest inconvenience. I therefore deem itdue to the patentee’s ingenuity, as well as to the public welfare, to give this deliberateopinion at a time when the volatile spirits of turpentine are getting into general use,and when, if burned in lamps on the argand plan, they must create danger.

Great care must be taken in the choice of the spirits of turpentine as the combustible.As those very generally sold in London contain rosin and other impurities, they arequite unfit for that purpose ; but the spirits manufactured by Messrs. John Tall andCo. of Hull, to be had of their agents, Ratcliffe and Co., 103 Hatton Garden, London ,answer perfectly. I have subjected these spirits to careful chemical examination, andI find them to be quite pure, and very different indeed from those on common sale here.Their specific gravity is only 0-864 at 62° Fahr., while that of the average London article is from 0-874 to 0-882, the greater density being due to rosin. Messrs. Tail’sspirits may be boiled off in a retort without leaving any sensible residuum, and they

also boil at a lower degree of heat; but the best proof of their excellence, in the present

point of view, is exhibited in the preceding notice of the Vesta lamp, for it was Mess'rs.Tail’s spirits which were used on that occasion. •

VENTILATION. There are two general plans in use for at once diffusingand renewing the air in extensive buildings, w-hich plans differ essentially in their prin-ciples, modes of action, and effects. The oldest, and what may be called, themethod, consists in planting stoves in the passages or rooms, to give warmth in colweather, and in constructing large and lofty chimney-stalks, to draw air in hot weathout of the house, by suction, so to speak, whereby fresh air flows in, to maintain, thou-imperfectly, an equilibrium of pressure. In apartments, thus warmed and ventilate ;the atmosphere is necessarily rarer than it is out of doors, while, in cold weather,external air rushes in at every opening and crevice of door, window, or chimney •fruitful source of indisposition to the inmates. rs

The evils resulting from the stove-heating and air-rarefying system were, a few 5’ ea r( jago, investigated by me, in a paper read before the Royal Societj',* and afterwa

*1 had been professionally employed by a committee of the officers of the customhouse,^^amine the nature of the malaria which prevailed there, but I had no concern in erecting tnwhich caused it.