a difficulty in suspending such trusses so as prevent them from changing their place. Where persons are inclined to corpulency, the weight of the intestines, making a constant pressure on the lower part of the abdomen, sooner or later causes the integuments to yield, and the lower part of the belly then projects in a way to be very uncomfortable, especially to those who, from motives of exercise, business or pleasure, are much on horseback. Belts of various kinds are applied in such cases, but generally with small effect, because it is difficult to make them pass in the right direction, and because they are very liable to shift their place. Mr. Bunney makes his belt (for whichever of the above-named uses it is intended) an essential part of a pair of drawers, either of silk or cotton, made to fit extremely well, and supported partly by common braces and partly on the hip bones: he likewise inserts, when necessary, a small pocket containing a ball covered with leather, the pressure of which is quite sufficient to keep up any recent rupture. Professional evidence of the novelty and utility of this invention was laid before the committee. Mr. J. Roberts of St. Helen's, Lancashire, has received from the Society of Arts their silver Isis medal, for his adaptation of Reflectors to the Miner's Lamp, invented by Sir H. Davy, THE principal objection to the use of Sir H. Davy's safe lamp is the feeble light which it gives, in consequence of the flame, which is not large, being enclosed by a cage of wire gauze ; and this defect is greatly increased when, as often happens, the miner is at work in air mixed with so much inflammable gas or carbonic acid, or a mixture of both, as to occasion the lamp to burn with a pale smoky flame. The explosion which, in such circumstances, would probably take place, is, it is true, prevented by this admirable invention; but any means by which the light of the lamp could be increased, or at least rendered more available to the miner, without impairing its safety, would greatly add to its utility. Each miner has, or ought to have, his own lamp; of which the only part of the light that is directly useful to him is that which falls on the spot where he is working: it is obvious, therefore, that if a reflector were placed behind the flame, much of the light that otherwise would be lost may be thrown to the preoise part where it is wanted. The reflector employed by Mr. Roberts is of no regular curve, but approaches to that of the concavity of about a third part of a cylinder: it may be made of copper silvered or tinned, or of planished tin-plate, which is not only the cheapest, but, on the whole, the best, as being far less liable than silver to tarnish by the contact of sulphureous vapour. In certain collieries, where the beds are thick, as at Whitehaven, and in the ten yard coal of Staffordshire, the miners are often required to work in the upper part of the galleries, where fire damp is very liable to collect, and where a lamp, even with a reflector, immersed in this inflammable air, will give but little light. For such cases Mr. Roberts employs a second concave reflector attached to the outside of the lamp by a jointed rod; which, enabling it to turn in any direction, allows the miner to place the lamp on the ground where the air is the purest, and consequently where the flame is the brightest, and by adjusting the exterior reflector, to direct the rays condensed by the interior one to the place where the light is wanted. Trial has been made of Mr. Roberts's apparatus in a colliery near Bolton, the under-looker of which reports that, by means of it, a degree of light, quite sufficient for every purpose, may be obtained at a distance of from fifteen to twenty yards from the lamp. Mr. Roberts, who is a practical coal-worker, stated the following circumstances to the committee, which, though not directly connected with the subject of the preceding notice, may perhaps, without impropriety, be recorded. Signs of the presence of inflammable air in a coal mine are, when the flame of the candle or lamp has a blue top, the length of such blue top being an indication of the proportion of inflammable air, and therefore of the hazard. This blue top is sometimes two and a half inches long; and when an explosion is imminent, it begins to dance on the top of the proper flame of the candle. Signs of the presence of carbonic acid gas are when the candle burns dull and finally becomes extinct, previous to which the flame becomes smoky, is somewhat enlarged, and the least agitation of the air will put it out. Signs of the presence of a mixture of both the abovementioned gases are, when the flame has a long broad bushy top, sometimes six inches high; the flame is then, in Staffordshire, said to be fire-fangled. In these circumstances no explosion takes place; but if the proportion of carbonic acid increases, the flame goes out. Those confined parts of a colliery which are imperfectly ventilated, and which, when cold, cannot be safely entered with a candle, cease to be so hazardous when warm. In such places the miner first enters without a light, takes off his jacket, and shakes it about to stir the air, and then falls to working with all his might till he is in a profuse sweat, in order that the place may get warm: he then steps out as quick as possible for his light, lest the place get cool: it is now safe as long as the miner continues at work; but if he ceases for a short time, the inflammable air shows itself by the blue top to his light, and the place becomes hazardous. If he leaves the place for a short time, he must re-enter it without a light, and with all the precautions above-mentioned. After a miner has been thus working, the vapour, as the place cools, will stand in drops of the dew on the surface of the coal... The efficacy of the above proceeding seems to depend, in part, on the carbonic acid produced by the breath of the miner, but chiefly on the aqueous vapour of his excessive perspiration; in confirmation of which Roberts found, while working in the coal mines of Whitehaven, that he obtained immediately the same advantage by throwing down before him a lump of quick lime and pouring water on it. Dr. Clanny's safe lamp depends on the same principle of diluting the gas with steam. AMERICAN PATENTS. (From the Franklin Journal.) For extracting cream from milk. S. Davis, New York. THE specification of this patent is in but few words; we therefore give it entire, as follows: "This improvement consists in putting zinc, commonly called spelter, into the vessel, or reservoir, containing the milk, or in depositing the milk in pans, or vessels composed of the aforesaid mineral, which decomposes the acrimonious substance that causes the milk to become sour, or rancid. And the same quantity of milk will yieldTM a greater quantity of butter, and of a much finer flavour. "What I claim is the manner of using the mineral called zinc, or spelter, in the reservoir, or vessels, contain VOL, VII. SECOND SERIES. Y 162 American Patents. ing the milk; and preparing vessels, or pans, from the zinc, or spelter. We believe this application of zinc to be really " new,' whether we may add " and useful," we very much doubt We cannot conceive of any action which can be exerted by the zinc, in an earthen milk pan, or of any which can take place between it and the milk, unless the acid of the milk, as it is formed, dissolves a portion of the metal, and in this case a poisonous salt will be formed. Zinc is among those metals which are most readily attacked by acids, and all its soluble salts are deleterious. If the effect is as stated, namely, that the milk containing the zinc will not become sour, or rancid, we know of no way in which this can be explained, but by the formation of metallic salt. APPENDIX To the Report of the Select Committee of the House of Commons, on Patents. Papers delivered in by John Farey, Esq. [British Law of Patents for Inventions.] DR. COLQUHOUN, in his Treatise on the Wealth, Power, and Resources of the British Empire, quarto, 1815, makes the following account of Parliamentary rewards given for useful discoveries previous to 1788. Note, they are all in addition |