In the Boucher process, the glass is first gathered from the furnace, but as no blowing-pipes are required, the gathering is done on a light iron rod, thus saving the gatherer much of the labour of carrying the heavy pipes. The requisite quantity of the glass so gathered is then dropped into the first or “measuring” mould of the machine, the “thread” being cut by hand by the operator. From the measuring mould, the glass is next caused to pass into the “neck” mould; the glass flows into this mould, and is further pressed into it by the aid of compressed air, applied above the free surface of the glass. At this stage the still liquid glass has the external shape of the neck of the bottle, but the mass of glass is solid, _i.e._, no cavity has yet been produced in it. The formation of the cavity is next begun by the action of a plunger which is driven into the “solid” mass of glass filling the neck mould, this plunger thus punching out the passage through the neck of the bottle. As soon as the plunger is withdrawn, compressed air is admitted into the cavity so formed, and the mass of glass is at the same time inverted, and that part occupying the position of what is to be the shoulder of the bottle is allowed to descend while being blown out by the compressed air. This process of distension is limited, and the desired shape is imparted to the mass by bringing towards it a third mould, by contact with which the glass is considerably stiffened--a row of jets of compressed air, impinging on the outside of the glass forming the shoulder of the bottle, being further used to stiffen the glass, once the requisite extension has been attained. The mass has now a shape very similar to that known as a “parason” in hand bottle-blowing, and is by this time decidedly stiff. It is now introduced into the finishing mould and is blown into perfect contact with the mould by powerful air-pressure, thus attaining the proper shape of barrel and base; the indentation of the base is, however, sometimes produced on a separate machine or press. During all these operations the neck of the bottle, which was the first part to be formed, has remained firmly held in the neck mould, and all the movements that have been described are performed by means of levers actuating movements of this mould as a whole, which, of course, carry the glass with them. The last movement of the levers, which releases the bottle from the finishing mould, also opens the neck mould, and thus leaves the bottle finished and entirely free.