in chemistry, an oblong or globular vessel with its neck bent, proper for distillation. See Chemistry, no. 576.

In the fifth volume of the Transactions of the London Society for the Encouragement of Arts, p. 96, we find a paper containing a method for preventing stone retorts from breaking; or stopping them when cracked, during any chemical operation, without losing any of the contained subject. "I have always found it necessary (says the writer) to use a previous coating for filling up the interstices of the earth or stone, which is made by dissolving two ounces of borax in a pint of boiling water, and adding to the solution as much flaked lime as will make it into a thin paste; this, with a common painter's brush, may be spread over several retorts, which when dry are then ready for the proper preserving coating. The intention of this first coating is, that the substances thus spread over, readily vitrifying in the fire, prevent any of the distilling matters from pervading the retort, but does in no wise prevent it from cracking.

"Whenever I want to use any of the above coated retorts; after I have charged them with the substance to be distilled, I prepare a thin paste, made with common linseed oil and flaked lime well mixed, and perfectly pliable, that it may be easily spread; with this let the retorts be covered all over except that part of the neck which is to be inserted into the receiver; this is readily done with a painter's brush: the coating will be sufficiently dry in a day or two, and they will then be fit for use. With this coating I have for several years worked my stone retorts, without any danger of their breaking, and have frequently used the same retort four or five times; observing particularly to coat it over with the last mentioned composition every time it is charged with fresh materials: Before I made use of this expedient, it was an even chance, in conducting operations in stone and earthen retorts, whether they did not crack every time; by which means great loss has been sustained. If at any time during the operation the retorts should crack, spread some of the oil composition thick on the part, and sprinkle some powder of flaked lime on it, and it immediately stops the failure, and prevents any of the distilling matter from pervading; even that subtle penetrating substance the solid phosphorus will not penetrate through it. It may be applied without any danger, even when the retort is red hot; and when it is made a little thicker, is more proper for luting vessels than any other I ever have tried; because if properly mixed it will never crack, nor will it indurate so as to endanger the breaking the necks of the vessels when taken off."