An entire revolution in the system of blocking straw hats was introduced in 1913-14 by a M. Stoffel, of Paris. This method depends for pressure on air only, and by its means shapes almost if not impossible by any other method can be beautifully blocked. The apparatus consists mainly of a vacuum reservoir from which all air is extracted, creating a suction pressure of about 13 lb. to the square inch, exhausted by means of a vacuum pumping engine and perforated blocks placed over copper tables that are also perforated and connected with the vacuum chamber. The blocks are of wood or metal, and both crowns and brims are made to the form of the outside of the hat, and are in themselves quite independent of the copper table. The _modus operandi_ is as follows: the block to be used is warmed by steam and is placed bottom uppermost on the copper table. The hat, slightly moistened by steam, is adjusted carefully on or in the block, covered with a large water and air proof cloth which can envelop the whole of the block and table, and leave a sufficient quantity to fill up the cavity caused by the interior of the crown, or the undulations of the brim. The vacuum force is then brought into action, and the suction created draws the cloth, with a pressure of about 10 to 12 lb. to the square inch, into every crevice or corner formed by the shape of the hat and block; the suction set up draws off as well any moisture evaporated by the heat of the block, and in a few moments the hat is sufficiently dry to be removed. By this method crowns of hats with concertina-like folds and creases can be perfectly “ironed,” using a block made of only two sections, whereas in any other form of blocking, where similar blocks must be made in five sections, the result obtained, comparatively speaking, is more or less imperfect. Moreover the process, while being much more rapid, does not require anything like the same amount of force expenditure on the part of the workman as do either hand or machine blocking. Another important benefit of this invention is that the actual working apparatus can be arranged in ordinary blocking benches, the copper perforated table taking up no more room than that usually occupied by a hand blocker, whereas, while other blocking machines do not occupy in themselves a greater area, the “roughing out” or “sweating” necessitates the ordinary hand blocking space which makes the actual amount nearly double. It must not be forgotten that the preliminary, as one may call it, apparatus of the “Stoffel” system requires space for the vacuum engine and pump, while the vacuum reservoir tank is, of course, of considerable magnitude, according to the services required. Both these, however, can be placed in some basement, etc., quite away from the actual blocking room. Whereas the earlier models need no extra area than the actual working spaces, with the exception of the steam generating plant, which,