Several other methods of alcoholometry, besides those already noticed, have been adopted at various times, but the majority of them possess so little accuracy as to be quite inapplicable to the purposes of trade, and of the laboratory. Thus, the strength was at one time estimated by what was called the ‘proof.’ A little of the spirit was poured upon a small quantity of gunpowder, contained in a spoon or saucer, so as just to moisten it, and was then inflamed. If at the end of the combustion the gunpowder took fire, the spirit was held to be ‘above proof,’ if it only languidly fizzed away, or slowly burnt, the spirit was said to be ‘proof,’ but if the gunpowder failed to ignite, the spirit was esteemed ‘below proof.’ Hence arose the terms ‘proof’ and ‘proof spirit,’ which have since been adopted by Act of Parliament. Another method was that of dropping oil into the spirit; if the oil floated, the spirit was considered to be ‘under proof,’ if it sunk, it was rated as ‘proof’ or ‘over-proof.’ The ‘gunpowder test’ is quite fallacious; for, if a certain quantity of a spirit is capable of firing the gunpowder, a little excess of a spirit 20% or 25% stronger will often fail to do so, so much water being formed as to prevent the ignition. The ‘PREUVE D’HOLLAND’ test, of the French, or the ‘BEAD,’ is still frequently employed by persons unacquainted with the use of the hydrometer. It consists in shaking the spirit in a phial, and observing the size, number, and duration of the bubbles or beads, as they are called. The larger and more numerous these are, and the more rapidly they break and disappear, the stronger the spirit is presumed to be. This method is unreliable, as the presence of sugar or acid, even in minute quantities, will sometimes give to a weak sample the appearance of one many degrees stronger. LOVI’S BEADS are also often employed to ascertain approximately the strength of spirit, when a hydrometer is not at hand. The insufficiency of most of the methods of alcoholometry here referred to, throws us back on the Revenue System (Sykes’ hydrometer), or on the specific gravity for unsweetened spirits. For sweetened spirits, as cordials, wines, beers, &c., there are none of the tests which give such accurate results as the distillation test, previously described as the Revenue Method.