can be easily taken apart and transported from place \ vantage. I refer to the manufacture, by mechanical to place by reulOving the bolts holding the sections, pressure, of nails. hexagonal nails, ete. The most praetieal forlll, how ever, seems to be the square taper nail shown in Fig. 2, whieh has about the sallie shape as the ordinary cut nail, but is somewhat stronger and a good deal tougher. It is well adapted for all ordinary purposes, but is espeeially suitable for a roofing nail, sinee the tin eoat ing prevents ulUeh rusting, a,nd is good to solder to. while witll wooden structures, nails and bolts being 'fhis nail was invented, in its original shape, by Mr. used, the timbers would become broken, split and de-Geo. H. Perkins, of Philadelphia, and has been de cay in a ,lion time. 'file roofs .are much cooler than veloped, through variou;; form8, uutil it has almost cOlTugated iron, but more expensive, while shingles reached a commercial stage-the machine in which it decay ill Ii year's usage. Asbestos aUlI gravel rooting is to be made, in marketable shape, being nearly com have not stood repeated tests, corrugated iron having pleted. The writer has been associated with 1\1r. Per gi veil the best sati�faction. kins in its development, and can, perhaps, llJake in-DU�lP CAHS-EVIUtAHD SYSTEM (Fig. 17).-1 saw teresting a brief description of the troubles we have llJany wooden systems of dump cars, built in some cases gone through in order to prod uce it quickly, at one of cl'eo,oted wood in order to resist the action of the operation, in a reasonably manageable and durable cliluate, iJut I found upon examination that all cars so machine.
