1831.] 
The Carainnassa Bridge. 
299 
Concerning the plan and progress of the work, a brief notice will suffice. Of the 
former, plate XVI. will serve to give a tolerably correct idea 1 . The original native 
bridge was to have had seven arches of 17 feet span : to take advantage of the piers 
already built it was determined to throw two of these into one, making three equal 
arches, which with the piers should occupy precisely 200 feet in span. I he seinicii cu- 
lar form was preferred on account of the great rise of the river, the necessary height 
of the road way, the symmetry of the elevation, (since for more than 8 months ot the 
year, the level of the water remains 2 steps below the spring ot the arch as shewn in 
the sketch,) and the convenience of cutting the stones to one model. The span of the 
arches is 53 feet, and the depth of the voussoirs 3 feet. A vault ot brick is laid ovu 
them to prevent any infiltration of water through the joints from above, lo the 
piers is given a section of 30 by 13 feet : the roadway is 2a feet wide, and pt i f» ct 1\ ho 
rizontal. The centering consisted of 6 frames, each composed of four pieces (fig. 3.) 
so as to be as light as possible; for it must be remarked, that no machine i \ < ould be 
employed in the construction: — every stone was to be raised and posited bj diicct 
human labour figures 5, 6, and 7 are intended to exemplify one instance ol tins 
in the simple native mode of carrying stones : the number of men is increased 
according to the weight to be lifted, and trom the combination ot le\er. , 
weight necessarily bears equally upon the supporting shoulders of .ill tin. pesraje 
or carriers ; with a sangar of 16 men they readily move a stone ot as many m ■ » 
or about fourteen cwt. f , 
Early in 1829, operations were commenced by embanking the western ia o 
rirer, as represented in fig. 2; the two piers required on the east being a rea y 
provided or needing but slight alteration, and the stones of the intermediate p 
the old structure serving, on removal, for the third new pier. 
Upon clearing the sand it was found, that coffer dams oi hot hi of stone 
laid down all across the river for a breadth of 60 feet, so as to convert the whole 
bed as it were into a solid rock. Most of these reached through the saiu y strut , 
20 feet deep, and rested upon the firm clay below 2 . Some ot them were a rea y 
filled up either wholly or in part with masonry, so that there was u i o 
difficulty in completing as much of the space as was judgei su cie 
supports the new piers. Such kothis as remained unfinished were therefore cleared 
of sand to as great a depth as could be attained, or until the under m^onry was 
met with, and were then filled with dhoka, or grouting of ioug i s outs 4 
lime, the latter of which forms an excellent hydraulic cement, as 
Proved by the difficulty of breaking away the old masonry ; three tom. 
ed stones brought the piers to the bed of the river, and six more o P 
the arches. In April 1830, the first arch was turned, and t e wo 
fenced ; but a sudden rise of 26 feet in the river, in the course ot one mg i . - 
away the whole of the centerings, fortunately without any materia ainag 
masonry. The two remaining arches were thrown over in the hot scaso . » 
a °d by dint of great exertion the roadway was made passable y > » 
1 W e have heard from the Raja, that he has deviated f ‘ rhe'fecessea on the 
graved in two respects : first, by omitting the semi-dom^ onthewitJg . 
P ,er «; and secondly, by substituting a plain parape o bavin" been previ- 
*alls ; his corrections arrived too late to be attended to, the plat . ° 
"•Kl are constructed oflong stones united together I., 
< Mi " fie. 4,) forming square chambers of about 15 feet JM*'. 
wooden frame or jamwat, which is sunken through the saud bj 
‘ggingj as practised by the well-diggers of Bengal. 
