When everything is ready for the proof, the windows are let close down, the door is shut and secured, and an iron rod heated red hot is introduced through a hole in the wall. On igniting the train, a tremendous explosion takes place. The windows are then drawn up, the door opened, and the smoke dissipated. The twist barrels are found buried in the sand, the common ones are thrown forwards; some are found perfect, others burst to pieces. It is rarely that best barrels are found burst; more frequently they are bulged, or swelled out, in places which are faulty, or of a softer temper. Those that are found perfect, are then marked with the provisional punch of different sizes (but having the same impression), according to the quality of the barrel. In London and Birmingham they have now an additional punch, containing the number of the bore by which the barrel has been tried. This mark easily enables the observer to discover whether the barrel has had any considerable quantity bored out after proving. Those that are bulged are sent to the maker, who beats down the swellings, and sends back the barrels to be proved again. They generally stand the second proof, though we have known a barrel undergo four proofs before it was marked. The common barrels are required to stand twenty-four hours before they are examined; when, if not burst, any holes or other material imperfections are made quite apparent by the action of the saltpetre. Such barrels are, of course, sent back unmarked. Those that are found satisfactory are duly stamped and taken home. The importance of the gun trade to England may be estimated from the number of barrels proved during the last year, 1857, of which the following is a correct statement:-- _Provisional Proof._ Plain iron barrels 185,776 Twisted barrels 136,804 Saddle pistol barrels 33,480 Best pistol barrels 962 Common pistol barrels 2,066 Revolving and double barrel pistols 57,106 ------- Total 416,194 Definitively proved, 70,100, being principally double barrels. This is in Birmingham alone; no doubt the London Company prove to the extent of 200,000 yearly, which may also be debited to Birmingham, as the barrels are all welded, bored, and ground before being sent to London. In addition to these may be counted the Government contracts of some hundred thousands yearly. The passing of this Act of Parliament levelled all distinctions between London and Birmingham proved barrels; they are now treated precisely alike, and one is equally good with the other. CHAPTER VII. THE SCIENCE OF GUNNERY. “Science begins at the point where mind dominates matter, where the attempt is made to subject the mass of experience to the scrutiny of reason. Science is mind brought into connection with nature.”--COSMOS.