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PREFACE.

imprudent, on the part of the Chester and Holyhead RailwayCompany, to have entered upon a work involving an immenseoutlay of capital, and on which the opinions of the scientificand engineering world were so much divided.

In conclusion, I have to express my obligations to severalscientific and highly valued friends, for having read over themanuscript, and suggested alterations in the narrative, andomissions in the correspondence, which have rendered the workmore concise, and I trust more acceptable to the general reader.I have further to acknowledge, that I am indebted to Mr. Tate,of Battersea, for the mathematical analyses, and for the in-teresting and valuable deductions and formulae, which will befound at the close of the experiments.

Manchester, June 1st, 1849.