212 REPORT— 1873. 



not be time for the iron to cool. With this view the rolls are driven at as 

 many as 5-50 revolutions per minute, giving (the rolls being about 7 inches in 

 diameter) a surface speed of about 1000 feet. 



The author then mentions how consecutive work is kept up by the two men 

 taking care to alternate their charges of rods into the furnace, so that while those 

 first put in are being rolled a second lot are heating. The operations of feeding 

 and of rolling each take thirty seconds. 



The author then enters into certain mechanical details as to how the rolls are 

 arranged to support the endway strain put upon them by the attempt of the plastic 

 iron in the grooves to spread sideways under the vertical pressure. 



The author then points out that it is an essential condition of obtaining good 

 work from pattern-i'olls that they should not be overheated, that they should not 

 be injured by the nearly fluid oxide adhering to the heated iron, and that the 

 objects produced should be able to leave the rolls with facility. He then describes 

 how the Messrs. Iluggett attained all these desiderata by causing a stream of coal- 

 tar to impinge upon the verj' channel or working chamber of the rolls, which 

 stream abstracts the heat, affords a lubricant, and at the same time supplies a film 

 (a mere microscopic one) of carbon between the heated iron and the surface of 

 the rolls. 



The author next remarks upon the necessitv of keeping such implements as 

 pattern-rolls in perfect repair, and states that with this object it has oeen wisely 

 determined never to allow the rolls to run for more than " one shift " without 

 adj ustment ; this being done daily, and being perft)rmed by the aid of appro- 

 priate tools, is a simple and expeditious operation, not more than -j^ of an inch 

 in thickness having to be removed. 



The author then proceeds to describe that the heated rod of noil-blanks, after 

 they are shot out of the rolls into tlie receiving-traj^, are pulled straight, and that 

 when cold they are presented, edgeways up, to the action of a pair of plain surface- 

 rollers, which press on the top of the prominences, and thus diminish their height 

 and proportionately' increase their breadth, by whioh means the metal in the 

 prominences is made to project in the direction of the width of the shank of the 

 nail, as well as in tlie previous direction, that of its depth, and is thus disposed in 

 the most suitable manner to be subsequenth^ formed into the heads. 



The author then reverts to the employment in this uiainifacture of the Siemens 

 Regenerative Gas-furnace, and points out how essential it is that for roUiug 

 (such as that which has been described) there should be none of that variation of 

 size which must occur by waste in an ordinary furnace ; and he shows how, hj the 

 ability which the Siemens furnace affords of giving not only a non-oxidizing but 

 even a reducing flame, the risk of waste is reduced to a minimum ; and states, so 

 successful has the application of this apparatus been to this particular manufacture, 

 that the total of furnace and rolling-mill waste is only .3 per cent., which, looking 

 at the small size of the iron heated, and the large proportion the surface bears 

 therefore to the weight, is an almost incredibly favourable result. 



The author then, proceeding with the description of the manufacture, states that 

 the flattened rods of nail-blanks are next taken to the cutting-machine, which has 

 three pairs of cutters, so that at each stroke it severs the rod through the pro- 

 minences, so as to cut out of each the future heads of two nails, and severs it 

 through the thin parts to produce the shanks of those nails, and the cut being on 

 a level forms at the same time the rudimentary point, while the third pair of 

 cutters shears off a small portion from the point, and thus regulates the nail to the 

 exact length. 



The author then describes the peculiar contrivances by which perfect squareness 

 of cut is obtained in these particular machines. 



The separated nail-blanks, it is stated, are then examined, and any that may be 

 imperfect are thrown out. After this the perfect blanks are subjected to friction 

 one against another in a slowly revolving cylinder called a " Rumbler," after which 

 they are annealed, certain precautions rendered necessary bj' tlie character of the 

 material and the nature of the article to be produced being taken. 



The author tlien dcFcribes the next process, the one that gives the true shape to 

 the head. This, it is stated, is done in a machine having a vertically reciprocating 



