340 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[October, 



struction of the mole. The contrary however happened, for the nuid 

 filled the port with slioals as far as the entrance, whereas before the 

 deposit was sutricientlv carried out by inundations, and by the recipro- 

 cal movement of the waters of the outer sea. Such are the defects of 

 the port of Ephesus (book 14, chap. 1). 



PERSIA, &C. 



Alexander in his expedition to Gedrosia was preceded by miners 

 to search for water (book IJ, chap. 1). 



In book l."", chap. 3, a bridge is mentioned as being thrown over the 

 Choaspes at .Susa. 



In the next page sluices are mentioned on the Tigris. 



In book V), chap. 1, an enumeration is made of the works of Semi- 

 ramis. 



Alexander destroyed a number of sluices on the river Tigris. He 

 also occupied himself with the canals, which are of the greatest im- 

 portance to the agriculture of that country (B. 10, eh. 1), a theme 

 upon which our author dwells at some length. He relates, on the 

 authority of Arisfobulus (see also Arrian, B. 7, f 22), that Alexander, 

 seated in a boat steered by himself, attentively surveyed the canals, 

 and caused them to be cleaned by employing a great multitude of men, 

 whom lie took with him. He also had certain outlets closed and new 

 ones opened. He remarked a canal, principallj' leading to the lakes 

 and marshes on the Arabian side, and the outlet of w hich, on account 

 of the softness of the ground, could not easily be closed ; he therefore 

 opened a new canal or mouth about 30 stades off, in a rocky ground, 

 through which he turned the waters. 



Egypt. 



In his 17th Book, Strabo describes Egypt. He mentions the skill 

 the Egyptians showed in hydraulic works, but the fact upon which he 

 nwells is partly perhaps attributable to Roman science. He says that 

 before the time of C. Petronius (ch. 1) Governor, A.D. 20, that the 

 greatest inundation and most abundant harvest took place when the 

 Kile reached fourteen cubits, but that under the administration of that 

 governor an inundation of twelve cubits produced abundance. 



In that book and chapter there is frequent mention of canals, and 

 there is a description of the canal of the Red Sea. (See also Diodorus 

 SieuluB, B. 1, s^ 1<.) and 33. 



Here also Strabo describes the Egyptian mortar as being made of 

 pounded basalt, brought from the mountains of Ethiopia. 



PAUSANIAS — iELIAN AND APPI.A.N. 



In Pausanias the only notices in any way relating to our subject are 

 an allusion to the silver mines of Laurium in the commencement of 

 the Attics, and in the Laconics a statement that Eurotas diverted the 

 river. In iElian and Appian there is nothing except perhaps that the 

 latter, in the account of the siege of Carthage, mentions a cut made 

 through the harbour by the Carthaginians. 



Arrian. 



Arrian in his Life of Alexander, 7th book, chap. 21st, gives a better 

 account than Strabo of Alexander's repair of the canal called Palla- 

 copas, although this latter account differs, we shall content ourselves 

 ■with a reference to it. We may observe that Gronovius has annexed 

 to his edition of Arrian a small treatise on this canal, which embodies 

 all the account and modern information respecting it. 



In his second book Arrian devotes much space to the siege of Tyre, 

 from which we shall extract some of his remarks on the mole. He 

 says that the sea there has a clay bottom, and shallow towards the 

 shore ; but when you draw near the city, it is almost three fathoms 

 deep. As there was abundance of stone not far off, and a sufficient 

 quantity of timber and rubbish to fill up the vacant spaces, they found 

 no great difficulty in laying the foundations of their own rampart ; the 

 stift' clay at the bottom, by its own nature, serving instead of mortar, 

 to bind the stones together. The Macedonians showed a wonderful 

 forwardness and alacrity to the work, and Alexander's presence con- 

 tributed not a little thereto ; for he designed every thing himself, and 

 saw every thing done. In describing the subseqiient operations Arrian 

 says that many engineers, meaning military engjpeers, were brought 

 from Cyprus and Phenicia. v 



In the fifth book a long account is given of the mode adopted by the 

 Romans, and particularly by the old Romans, in forming temporary 

 bridges for crossing large rivers. 



The Prilisli Queen Sleam-sliip. — This spU'iiiIid steamer sailed yesterday for 

 Anlvcrp. A select party of gentlemen went in her on a visit' to BelHiam. 

 The Briiish and American Steam Company have, it is said, received lor her 

 the sum of £00,000 from the Belgian government. For the President the 

 same cumpanv received above £70,000 from tlic underwriters. The losses 

 sustaineil Ijy the company since iis cstaWishment are supposed not to be less 

 than £80,000 nor more than llOO MO.— Liverpool Albion, Sep. G. 



OX THE MANUFACTURE OF BRICKS AND TILES. 



[We are indebted for the following article to a very useful work bv 

 Mr. Aikin, just published; we have appended some additional notes, 

 which we think will be found useful, and make the article more com- 

 plete. — Editor.] 



Till lately, bricks appear to have been made in this country in a 

 very rude manner. The clay was dug in the autumn, and exposed to 

 the winter frosts to mellow; it was then mixed, or not, with coal 

 ashes, and tempered by being trodden by horses or men, and was 

 afterwards moulded, without it being considered necessary to take out 

 the stones. The bricks were burnt in kilns or in clamps ; the former 

 was the original mode, the latter having been resorted to from motives 

 of economy. When clamps began to be employed I do not know: 

 but they are mentioned in an act of parliament passed in 1726, and 

 therefore were in use prior to that date. The following, in few words, 

 is the present process of brick-making in the vicinity of Loudon, for 

 the practical particulars of which 1 am indebted to Mr. Deville and 

 Mr. Gibbs. 



It is chiefly, I believe entirely, from the alluvial deposits above the 

 London clay, that bricks are made in the vicinity of the metropolis ; 

 and a section of these deposits generally presents the following series, 

 such as vfould naturally result from a mixture of stones, and sand, and 

 clay, and chalk, brought together by the force of water, and then al- 

 lowed to subside. The lower part of the bed is gravel, mixed more 

 or less with coarse sandy clay and pieces of chalk; this by degrees 

 passes into what is technicaUy called malm, which is a mixture of 

 sand, comminuted chalk, and clay ; and this graduates into the upper 

 earth or strong clay, in which the clay is the prevailing or character- 

 izing ingredient, the proportion of chalk being so small that the earth 

 makes no sensible effervescence with acids. Bricks made of the 

 upper earth, without any addition, are apt to crack in drying, and in 

 burning they are very liable to warp, as well as to contract considerably 

 in all their dimensions ; on this account they cannot be used for the 

 exterior of walls ; and a greater number of such are required for any 

 given quantity of work than of bricks, which, though made in the 

 same mould, shrink less in the baking. The texture, however, of 

 such bricks is compact, which makes them strong and durable. 

 Bricks formed of this clay, whether mixed or unmixed, are called 

 stocks ; it was formerly used unwashed, and when the bricks were 

 intended to be kiln-burnt, oijlame-bunil, to use the technical word, no 

 addition was made to the clay. If they were intended to be clamp- 

 burnt, coal-ash was mixed during the tempering. Of these and all 

 other clamp-burnt bricks the builders distinguish two kinds, namely, 

 the well-burnt ones from the interior, and the half-burnt ones, or place 

 bricks, from the outside of the kiln. 



The calcareous clay or malm earth requires no addition of sand or 

 chalk, but only of ashes. The bricks made of it differ from those 

 made of the top earth, in being of a pale or liver brown colour, mixed 

 more or less with yellow, which is an indication of magnesia. The 

 hardest of the malm bricks are of a pale brown colour, and are known 

 by the name of gray stocks; those next in hardness are called seconds, 

 and are employed for fronts of the better kind of houses ; the yellow- 

 est and softest are called cutters, from the facility with which they 

 can be cut or rubbed down, and are used chiefly for turning the arches 

 of windows. What I have said of top earth and malm earth must be 

 understood, however, to refer to well-characterized samples of these 

 varieties, but, as might be expected, there are several brick-fields 

 that yield a material partaking more or less of the qualities of both, 

 and therefore requiring corresponding modifications in its manu- 

 facture. 



Brick earth is usually begun to be dug in September, and is heaped 

 rough, to the height of from four to six feet, on a surface prepared to 

 receive it, that it may have the benefit of the frost in mellowing it and 

 breaking it down. It is then washed by grinding it in water and 

 passing it through a grating, the bars of which are close enough to 

 separate even small stones. The mud runs into shallow pits, and is 

 here mixed with chalk ground with water to the consistence of cream, 

 if any calcareous ingredient is required. Wlieu it has become tole- 

 rably stifl'by drying, coal ashes (separated by sifting from the cinders 

 and small pieces of coal) are added, in the proportion of from one to 

 two and a half inches in depth of this latter to three feet of clay, the 

 most tenacious clay requiring the greatest quantity of ashes. The in- 

 gredients are then to be weU mixed ; and, finally, the composition is 

 to be passed through the pug-mill,* in order to complete the mixture 



* The pug-mill is an iron cylinder set upright, in the axis of which an 

 arbor or shaft revolves, having several knives, with their edges somewhat 

 depressed, projecting trom it and arranged in a spiral manner round the ar- 

 bor. By the revolution of the arbor the clay is brought within the ac'.ion of 



