38 ANNUAL OF SCIENTIFIC DISCOVERY. 



was about 20. A large steam-power machine for the manufacture 

 of both solid and hollow brick was shown in operation, by H. Clay- 

 ton & Co. This machine was a " combined three-process machine " 

 for clay-crushing, pugging, and brick-moulding at one time. It is 

 worked by a 12-horse power engine, and is capable of turning out 

 from 20,000 to 30,000 solid, perforated, or tubular bricks per day, 

 according to the quality of material used. The exhibitors claimed 

 that, combined with their patent system of kilns and drying appara- 

 tus, these machines have, where they are adopted, reduced brick- 

 making to a regular factory system, which can be carried on, inde- 

 pendently of seasons or weather, uninterruptedly throughout the year. 

 The peculiar mechanical difficulties necessary to be overcome in the 

 production of a practically successful brick-making machine do not 

 seem, however, to have been as yet accomplished. All experiments, 

 necessarily, have had to be conducted on one of two essentially 

 different principles: by "compression," i. e., forcing the clay, either 

 in a wet or dry state, into moulds to form the brick ; or by " expres- 

 sion," i. e., forcing the clay, in a plastic state, through a die which 

 should consolidate and shape it during its passage. Both processes 

 have been extensively and variously tested. With the former, great 

 difficulty has been found in perfectly filling the mould, whether with 

 wet or dry clay, the lower corner of the brick remaining imperfect, 

 even after the clay had been submitted to enormous pressure while in 

 the mould. Another difficulty was in delivering the brick from the 

 mould rapidly, and without injury to its form. In the use of dry clay, 

 the inconvenience from each of these causes was, perhaps, somewhat 

 less felt, but this involves the erection of an apparatus for crushing 

 and sifting, beside the cumbrous and expensive pressing machine, 

 and the quality of brick so produced is not generally admitted to 

 equal that made from plastic earth. In the " expressing " machines a 

 serious difficulty was experienced at the outset in moulding through 

 dies so as to form a perfect rectangular stream of solid clay, the 

 increased friction at the angles of the stationary plate die causing the 

 mass to come out ragged at the edges, at times fracturing even the 

 brick itself. Very many methods have been tried for obviating this 

 difficulty, and in the Clayton machine, above noticed, it is claimed to 

 have been effected by giving to the die orifice revolving sides. The 

 working surface of the die-rollers is, further, constantly lubricated 

 by means of branch supply pipes passing down from a water reser- 

 voir above. The clay comes out alternately on the two sides of the 

 machine in a continuous, smooth, and solid stream, with sharply-de- 

 fined angles, and there remains only to cut it in proper breadths for 

 forming bricks. There were, beside this, a score of brick-machines 

 exhibited in the building, from Great Britain and various European 

 countries, indicating that whatever apathy may have existed on this 

 subject in the past, there is none now, and that the days of hand 

 brick-making are over ; for from among so many, each possessing, 

 doubtless, some merit peculiar to itself, there must, ere long, be educed 

 a machine for manufacturing " perfect bricks " with economy, even if 

 it has not already been effected. 



The display of glazed stoneware in the English department was 

 most extensive and interesting. As examples of novel applications 



