336 



SCIENCE. 



[Vol. XIII. No. 326 



gravel found in many clay banks. There are machines for separat- 

 ing the larger stones and crushing the smaller stones, which work 

 very well excepting where there is limestone. The only remedy 

 for that species of clay is washing, which is too expensive for com- 

 mon brick-making. A machine that will separate all gravel or 

 other hard substances from the plastic clay, and leave it fine enough 

 to be worked into terra-cotta, has been tested, and fulfils all the 

 requirements. It is very simple, and will separate large quantities 

 of clay with very little power. This machine will help manufac- 

 turers to use clays which at present are worthless, but which may 

 become sources of wealth when passed through suitable ma- 

 chinery. 



Some may smile at the idea of making bricks by machinery, but 

 it is believed that brick-making by hand will soon become a thing 

 of the past. The stiff-clay, machine-made brick will be used for 

 paving purposes, bridges, docks, tunnels, and all works that require 

 great strength ; while dry-pressed brick will become the building- 

 brick of the future. 



Four specimen bricks made by the tile company mentioned, and 

 picked up at random, were submitted to a test by the Chicago 

 Forge and Belt Company about three years ago. The ultimate 

 crushing resistances of the samples were 252,000, 228,000, 210,000, 

 and 318,000 pounds respectively. The bricks measured 7^ by 2j 

 by 4 inches. 



The construction of a brick pavement is a simple matter. The 

 foundation being brought to the proper grade, there is spread over 

 it six inches of gravel or sand, which is struck off with a board 

 gauge fitted for the grade of the street. A course of brick is then 

 laid on the flat surfaces, running lengthwise the street. It is not 

 necessary that this course should be as hard as the upper course, 

 being only a foundation for the brick that will receive the wear. 

 Over this an inch of screened sand is spread, gauged, and properly 

 smoothed off. The top course is laid with the bricks on their 

 edges, lengthwise across the street. Care is taken to break joints 

 in both courses. The whole is covered with an inch of screened 

 sand, which is swept into the crevices. After this is done, a roller 

 weighing five or six tons is passed over the pavement several times. 

 If the street is properly rolled, it will be as smooth as wooden 

 pavement, and almost as noiseless. 



The street should be drained in some manner, as the lasting 

 qualities of the brick and the even surface of the street depend to a 

 great extent upon the drainage, as it is a well-known fact that 

 ■water weakens brick very much. It would be a good plan to run 

 a six-inch drain tile outside of the curbing, connected with a four- 

 inch tile running through the curbing at the corner of each block. 

 This will carry off all surface water ; and, if the six-inch tile is 

 about three feet below the surface, it will drain the sides of the 

 street, so that water will not reach the foundation of the street. 



The upper course should be very hard. The brick should be 

 vitrified. It may be objected that if they are burnt to a glassy 

 surface they will chip off or be crushed. That objection is not sus- 

 tained. In Decatur are whole blocks paved with brick as smooth 

 as glass and as hard as flint, and no brick of that description shows 

 any signs of wear. The wear comes on the objects passing over 

 the bricks, which are harder than steel, for a file will not scratch 

 them : in fact, when broken open, they resemble flint. 



Horses do not slip or fall on brick pavements as they do on 

 granite blocks, owing to the small surface between the seams. An- 

 other advantage possessed by vitrified brick is that they will not 

 soak water. If water and frost are kept out of brick, they are al- 

 most indestructible. Professor R. T. Brown says, "Clay well 

 burned is as nearly a neutral substance as any in nature : its ele- 

 ments, being well united and in chemical equipoise, have no af- 

 finity for other substances that might disengage them from their 

 combination. It is therefore chemically indestructible." 



The Decatur Tile Company laid a block of brick four years ago, 

 on a private contract, agreeing to make all repairs for five years 

 free of charge. The street has not yet needed any repairs what- 

 ever, and from present appearances it will not be necessary to 

 make any for the next twenty years. The first cost of such a 

 pavement is low, the best pavement in Decatur costing only from 

 $1.25 to S1.50 per square yard. 



It was formerly thought that only certain kinds of clay could be 



used for paving-brick, and the Decatur Tile Company is believed 

 to have been the first to make it of common clay. Now there are 

 a number of factories using the same kinds of machinery, and 

 making the same quality of brick from such clay. 



The following, from the Clay Worker, is of interest in this con- 

 nection : " Brick-making has been dormant for nearly thirty cen- 

 turies. From the time that clay-workers moulded and burned the 

 bricks for the Royal Palace of Nebuchadnezzar, and stamped the 

 royal signet on them, till the beginning of the present century, not 

 a single step had been taken toward improvement in any of the pro- 

 cesses involved in making and burning brick. Within the last fifty 

 years, however, brick-making has been waked to new life, and now 

 scarcely one of the old processes in its original form remains. 

 Every thing, from the selection of the clay, to its preparation,, 

 moulding, drying, and burning, is stamped with innovation, may 

 we not say with improvement } Machinery has been called in to 

 aid this march of progress ; and what had been the drudgery of 

 hard labor, from the days when the Israelites toiled in the brick- 

 yards of the Rameses, is now thrown on the broad shoulders of 

 steam-power." It may be added that the greater improvements 

 have been made in the last seven years, and still greater may be 

 expected. By bringing the fuel and clay together with proper ap- 

 pliances, we may have good, clean streets in all our cities. And it 

 would pay the farmers well if brick pavement should be extended 

 into the country, as it would enable them to market their produce 

 in winter, when otherwise the roads are impassable. It would also- 

 do away with road-taxes for a generation at least, for a road prop- 

 erly paved with hard brick ought to last fifty years, with very little 

 repair. For a road paved, fifteen feet wide, with two courses of 

 brick, at the prices of material and labor already given, the cost would 

 be about ten thousand dollars per mile. Such roads might be 

 considered expensive, but they would prove to be a good invest- 

 ment in the long-run. J. G. SHEA. 



A FIVE-MASTED SAILING-SHIP. 



The preference of ship-owners for large cargo-carrying vessels- 

 is becoming more and more pronounced, and the companies more 

 particularly engaged in the part of the shipping trade in which 

 sailing-ships are worked seem to vie with each other in securing 

 " the largest ship afloat." Intimation is given in Engineering that 

 a contract has been placed with a firm on the Clyde, who make the 

 building of sailing-ships a specialty, for the construction of a five- 

 masted steel sailing-ship to carry 6,000 tons dead weight. Not 

 only will this be the first five-master, but it will be the largest sail- 

 ing-ship afloat. At present a vessel named " Liverpool " has this 

 distinction. She has a gross tonnage of 3,330 tons, her length be- 

 ing 333 feet, breadth 47.9 feet, and depth 28 feet moulded. Bro- 

 kers, too, like the big ship, and the reason is so evident that it is 

 not necessary to refer to it ; but underwriters do not seem so much 

 enamored with it. Quite recently one of the largest vessels — 

 shorter by 10 feet, but broader by i-J- feet, than the " Liverpool " — 

 was chartered to take coal ; but, when all the debatable points of a 

 charter were settled, the underwriters had to be reckoned on, and 

 they desired such a premium as made it quite impossible to pro- 

 ceed further in the matter, — something like ^ 10 to ^ 15 per;£ 100^ 

 They contended that the greater the quantity of coal carried, the 

 greater the danger of fire. This vessel, however, has made several 

 voyages, and no difficulty is now being experienced with the in- 

 surance firms. They will be educated to a higher standard, al- 

 though at present a little conservative. There is another difficulty, 

 however, which cannot be so readily overcome. Such large vessels 

 can only be employed profitably in certain trades, and great incon- 

 venience must arise unless suitable graving dock accommodation 

 can be afforded at the large trading ports. No difficulty will be 

 experienced at home ; but in Calcutta, for instance, one of the big 

 ships now afloat presented itself recently for admittance to the 

 dock, and it was found that her beam was too great ; and yet boats- 

 with more beam will be built. The result was that she had to- 

 load, and hope for better accommodation at her next port. San 

 Francisco and New York have large docks, but the importance of 

 Calcutta port for ships cannot be ignored. 



