186 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[June, 



The ceiling of it is formed by beams of stone laid transversely; but 

 at the intersection of the cross is a cylindrical column supporting a 

 square slab of stone or abacus, forming the ceiling of the chamber at 

 that part. The interior is richly ornamented with different kinds of 

 mosaic fret, and is painted with vermilion. If we may judge from 

 the ruins of their sepulchres which still exist, the Toltecan nation 

 must have paid the greatest respect to the memory of their dead. 

 Occasionally we fiud them deposited in ca*-erns wrought by hand, 

 similar to the one we have just spoken of; there is likewise one of 

 the same cruciform shape at Chilan, and another, containing three 

 chambers, near Xochicalco ; but most commonly they constructed a 

 large conical heap or tumulus, and faced it with stone or brick ; through 

 this was made an arched passage usually running north and south. A 

 tumulus of this kind at Mount Alvan has one side of this passage 

 lined with oblong slabs of granite carved with human figures. There 

 is a very remarkable sepulchral monument situated likewise at Mount 

 Alvan; it is constructed in a conical hill like those before mentioned, 

 but there is also an arched passage running east and west, intersecting 

 that running from north to south. At this intersection is a large and 

 well constructed rotunda, the dome of which is somewhat in the shape 

 cf a parabolic conoid ; the sides and interior are lined with good ma- 

 sonry, and at the top is a kind of funnel or chimney going right 

 through to the exterior summit of the tumulus ; this was probably used 

 for purposes of ventilation. 



The Toltecans generally made the arches of their bridges square 

 headed, by means of a stone lintel laid across from pier to pier, but 

 not unfrequently they placed long beams of stone leaning towards one 

 another at an angle of about 55 degrees, and meeting at top, forming 

 a kind of triangular straight-sided arch. In the province of Thascala 

 are the ruins of two bridges of this latter description, and the angles 

 of the roadway are ornamented with four piers or obelisks, of about 

 50 ft. in height, having an imposing effect. There still exists at Chil- 

 Luittan a bridge very peculiarly constructed by means of large blocks 

 of stone, the upper surfaces of them being cut convex and the lower con- 

 cave, springing from their piers and meeting together at the crown of 

 the archway. The arch thus formed bears a great resemblance to 

 our Gothic " Lancet." 



Perhaps it may be as well to say something of the roofs, doors, and 

 ■windows of the edifices we have been describing. Of the first the 

 interior frame was in most instances triangular, the angle at the apex 

 being rather acute ; but there are examples in the form of an inverted 

 cyma, somewhat like the roofs of the Chinese buildings. Internally 

 the sections of the ceilings were sometimes plain-sided triangles 

 (occasionally truncated), at others they were graduated in overhanging 

 courses, forming a kind of arch. The doorways were of a square or 

 oblong form, having merely a plain stone lintel resting on its piers. 

 Very many of the windows and niches are of the same description, 

 but we find in them a much greater variety of form. They are some 

 cf them arched at top, some triangular, some in the shape of the 

 Egyptian Tau, while others resemble the trefoil-headed Gothic arch. 



PROTECTION OF LAND AGAINST THE SEA. 



The expedient about to be described was put into practice at a part 

 of the Moray Firth, near the town of Inverness, North Britain. 



There was great reason for supposing that the Firth had encroached 

 enormously at this place ; and so certain and rapid seemed its progress 

 towards the destruction of a portion of the carse land known by the 

 name of the "Longman," lying between it and the rich town lands 

 immediately contiguous to Inverness, that the inhabitants, foreseeing 

 the certain destruction which awaited the town lands, and perhaps 

 ultimately Xhe town itself, if the carse land, which had by this time 

 been reduced to an average breadth of about 100 yards, were not 

 protected, determined upon erecting a very substantial wall, (A) as 

 represented in the annexed sketch, and it was hoped that the evil 



would be thereby effectually cured ; but after resisting the action of 

 the water for some years by the aid of almost constant repairs, it was at 

 length so much damaged that proposals and estimates were submitted for 

 the purpose of erecting another waU of much stronger dimensions, 

 and the inhabitants were preparing for another serious demand upon 

 their purses, when they were agreeably surprized by receiving a pro- 

 posal from Mr. William Hughes, then a contractor upon the Caledonian 

 Canal, to protect the town lands effectually, and that at no cost what- 

 ever to the town, as he required no farther remuneration than the 

 possession of the stones of which the wall had been formed. This 

 agreement was eagerly entered into on both sides, and both parties 

 were perfectly satisfied with the result. 



Suture qf Citrac^lajiS' 



- — — as — 



The contractor's mode of operation was extremely simple, as may 

 be seen by the sketch : the beach ascended from low to high water- 

 mark at an inclination of about 1 in 9, and then rose abruptly about 

 3 ft. to the level of the carse lands. Having removed the old wall, 

 the contractor considered that nothing more was wanting than the for« 

 mation of a beach of sufficient solidity to resist the action of the 

 water, and having at the same time such a section as to allow the 

 waves to exhaust themselves without meeting %vith any substance 

 which might be injured by them. These objects were attained by 

 removing sufficient stuff to admit of the beach being carried up and 

 terminated by a gentle curve tangent to the original beach, whilst the 

 surface of this newly-formed beach, and also down towards low water- 

 mark, was rendered solid by excavating a foot in depth, and depositing 

 therein boulders found on the beach. This formation is represented 

 by B in the sketch ; and we have only further to add that nothing 

 could have proved more creditable to the contractor, or more service- 

 able to those interested in its success, since, from the time of its com- 

 pletion till the present time, a period of not less than 26 years, the 

 town has not lost one foot of land, nor been put to any expense for 

 repairs. 



H. 



NOTES ON EARTH WORK, EXCAVATION, CUTTING, AND FORMING 

 EMBANKMENT UPON RAILWAYS. 



Article II. — Plant, Haulage, and Contingencies. 



" Modern practice has reduced it to a price per cubic yard." 



Professor Vignoles^ Lecture, Dec. 1841. 



The rails, wagons, sleepers, &c. used by contractors, are called the 

 " Plant," and are of a lighter description than those used for permanent 

 works. The rails range generally from 26^ to 30 lb. per yard, and the joint 

 pedestals or chairs 20 lb., and intermediate chairs 12j lb. each. The follow- 

 ing were the prices paid in 1837: — rails 13/. per ton ; chairs 9/. 10s. per 

 ton; keys 24i. per cwt. ; sleepers Is. to Is. 3rf. each. The plant required for 

 the conveyance of 213,000 cubic yards of earth with embankment consisted 

 of 157 tons of rails, 67 tons of chairs, 28 cwt. of wedges and nails, and 42 

 wagons, estimated to contain or carry \\ cubic yards each, costing 18/. 10». 

 each,* and 96 to contain 2\ cubic yards each, costing 23/. each. The cost 



* Wagons to contain H cubic yards of earth, of which 42 were used — 

 cost £777. 



1 set of wrought iron work pedestals, bolts, and hoops,390 lb. £.. s. d. 



at 4rf. . . ... . . 6 10 



1 set of 24-in. wheels and axles . . . . 7 15 



19cubicft. of elm.at 3s. 2 17 



Labour of making each . . . . .18 



18 10 



Wagons to contain 21 cubic yards, of which 96 were used, each 23/.— 

 cost £2208. 



