Chap- X.

VALUE OF ARTIFICERS’ WORKS.

905

anil point are injured, and before it can be used again as a pile, or converted to any otherpurpose, it must be reworked, and reduced to 4 metres in length. The length of thepile will then have diminished a quarter of the interval from i metre to 5 metres : theprice of the cube metre of timber must then be diminished a quarter of the interval between75 and 25 francs; that is to say, it will be reduced to 62 50; consequently, if the pile is25 centimetres in diameter, it will be worth 4 x0-48=0"192 cube metres, at 62-50 francs;that is to say, 12 francs : but, according to ordinary custom, the contractors will take it at4-50 x 0-048 = 0-216 cube metres at 37*50 francs, that is to say, for 8*10 francs.

A piece 30 centimetres square, employed as a binding piece to a centre, and in whichnotches 10 centimetres in depth have been cut. and at the extremities a joint 50 centi-metres long, will have sustained a loss of one metre in length, which will reduce the priceof a cube metre of such timber to 62‘50francs. The notches do not affect the value, becausea cube metre of timber 30 by 20 centimetres square is not essentially worth less than a cubemetre of timber 30 by 30 : hut the piece must be considered as having lost one-third ofits thickness ; thus it is not worth more than 4 x 0 030 x 0-20 = 0-24 cube metres at 62 50francs ; that is to say, 1 5 francs.

According to custom, in the first example the contractor would be a considerable gainer ;in the second, he would neither gain nor lose. As in carpentry, there are few timberswhich belong to the second example, but many of the first which are little injured,it follows that the contractor obtains an advantage, if care be taken that the piecesbe as little notched as possible, and the binding pieces attached by bolts: hence itappears that if an account is not taken of the loss which each work sustains, and a gene-ral proportion adopted, the contractor should take the timber back at two-thirds; that isto say, allowing one-third for use and waste; nevertheless it must be observed, that itoften happens that the timber remains a long time on hand before it can be again used :this requires consideration, and perhaps a further allowance to be made.

There are temporary works executed with timber that has been previously employed forthe same purpose, as cofferdams: on examining, if it requires any change in construc-tion, the extra labour must be taken and valued accordingly : as for the loss sustained byrecutting the timber, the proportion is the same as has been already given, or at abouta fourth of the primitive volume.

Incidental Expenses for Carpenter's Work are considerable, independent of the expenses ofmanagement, which comprise the payment of the foreman, who marks out the timber,regulates the employment of the men, and that of the clerk, who enters an account of thetime and materials : besides these, there is the rent and expenses in the yard, the costof sheds for laying out the moulds, the machines, as pile-engines, crabs, scaffold-poles,blocks, and pulleys, windlasses, trucks, &e.; keeping them in order, and above all, thecordage and ropes, which are a considerable item of expense ; the tools also which are notprovided by the workmen but found by the master, of which there are several. These inci-dental expenses may be estimated at one tenth of the value of labour.

For the price of a cube metre of timber used in the platform of a foundation, supposingit framed, and fixed under water; the price of the timber per cube metre delivered at theyard being 75 francs : the carpenter’s day’s work 3-5 francs, and the labourer’s 2 francs. Theplatform, 10 centimetres in thickness, may be formed out of timbers 30 centimetres square,by putting two cuts into it, or of timber 20 centimetres square with one cut; conse-quently, in the first instance, there will be 6-667, in the second 5, and the mean 5-853square metres of sawing for a cube metre of platform. The price of the cube metre willthen be valued as follows : —

Francs

75-00

2-86

Francs.

A cube metre of timber furnished -

5*833 square metres of sawing at the rate of 1 -4 hour of a

77-86

carpenter, valued 0*49 franc per square metre -An eighth for loss -

Carriage, distance 200 metres, 0"47 hours of a truck.

9-73

'8-29

worked by 10 labourers, worth 2 francsLabour for framing, sinking and adjustment under water,

31 hours of a carpenter at 0-35 francsA tenth of the labour for incidental expenses

0-83

Total

96*71

9-67

A tenth for the contractor’s profit -

Total

106-38

For the principals of a centre used in a stone bridge, composed of two arches, which are

separately centred, the dimensions being unequal, so that it would be required to recut