PREFACE.

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It may not be improper, before concluding, to in-form the reader, that my qualifications for the taskI have undertaken are founded upon many yearsexperience, during which time, I possessed peculiaropportunities to witness and verify the most ex-tended series of operations that ever have beenmade for the purpose of ascertaining the practica-bility, safety, and general nature of the art of apply-ing coal-gas as a substitute for tallow and oil; andwhich have, as it were, fixed the fate of this art.The numerous experiments I instituted, upon a largescale, by desire of the Gas-Light Company, for thepurpose of adducing them in my evidence beforethe House of Commons, and House of Lords , on aformer occasion, have enabled me to collect such in-formation as could not have been obtained by othermeans. The substance of these results ( which areprinted by order of Government,) are incorporatedin this Treatise , together with such other facts andobservations as have presented themselves in theroutine of my profession elsewhere.

To generalize the results of my observations, andto make them practically useful to the public, is theaim of the present publication, and I need scarcelyadd, that their suffrages to the zeal and industry, atleast, with which I have endeavoured to attain myobject, will be a source of infinite satisfaction.

FREDRICK AC CUM.

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