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ENTERED according to Act of Congress, in the year eighteen hundred and fifty-nine


In the Clerk's Office of the District Court of the United States for the Northern District of California.



THE frequent inquiries, by Engineers and Surveyors, for a field-book of reliable and useful tables, have induced me to undertake the publication of a work of this nature, which might contain everything that could be required in the execution of a survey. Through the co-operation of DR. R. C. MATTHEWSON, a gentleman of acknowledged mathematical ability-and to whom, indeed, the following work chiefly owes its merit-I am now enabled to present to the profession a compendious and, it is hoped, a highly useful Pocket Companion, in the preparation of which no labor has been spared to make it what it assumes to be. The First Part contains a description of telescopic measurement, with its advantageous application in a rough country; a brief review of mathematical and scientific instruments, together with rules for their adjustment and use, copiously illustrated with fine engravings on wood. In the Second Part may be found all those tables and rules which are continually required in the field, and without which much time would be lost in tedious and difficult calculations.

As the sale of a book of this kind is necessarily limited- the proceeds falling far short of its actual cost-I have resorted to the method of subscriptions, and am happy to state that the members of the profession have most liberally seconded me in my effort. To them I beg leave to tender my sincere thanks.

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