This may be explained, without impeaching the sagacity or accuracy of those engineer, by the facts, that they had no actual experience derived from the price at which contracts would be taken that the difference in the cost of land from that which it bore in 1835, and that afterwards placed on it by speculators and interested persons, was beyond calculation and that the prices of work and materials were largely enhanced between 1835 and 1837. "The whole project, in fact," say the Com- " was missioners, entirely new, and perhaps without precedent as to cost, and therefore it

o%ht not to be considered as a want of talent, that mistakes were made in estimating the

expense." In confirmation of these views, and of the great liability to error in estimates for undertakings of such a nature and extent, the reader will recall the fact stated in the Prelimi- * nary Essay, that almost all the estimates for the various water works of London, fell vastly short of the actual cost.

On the 27th of December, 1837, after he had placed thirteen sections of the first division under contract, and therefore with some practical experience of the value of such

work, Mr. Jervis made an estimate of the cost, so far as the engineering was concerned, of the whole line, which amounted to $7,877,346 00 This was exclusive of the cost of land, salaries, and other expenses, which the Commissioners themselves estimated at 586,567 00

$8,464,033 00

For the additional cost of the high bridge, 443,432 00