Extracted, and sold separately, from Simms's work on Levelling, being pp. 139-215. LONDON: JOHN WEALE, 59, HIGH HOLBORN. 1856. PREFACE. THIS little volume has been prepared almost entirely with reference to the wants of young men who desire to qualify themselves for field service in an Engineer Corps. On that account the plainest language has been used to render the subject intelligible,-dispensing with mathematical brevity. The Table of Natural Sines and Tangents to single minutes, in a form sufficiently portable for field use, will supply a want which is frequently experienced, not only in the operation of laying out curves, but on many other occasions. One object in preparing it, was to furnish the profession with a Table that should be not only portable, but absolutely reliable. Those whose occupations compel them to resort to the Tables in common use, must have frequently experienced the embarrassment which attends the inaccuracies to which they are all subject. So long as a Table is known to contain a single error, the position of which is not ascertained, its employment is attended with doubt in every instance in which we are obliged to refer to it. As Hutton's Tables of Natural Sines and Tangents are those most in use among the profession, it will be desirable to those persons who possess them, to be able to correct the following errors, which I detected in comparing them. In Hutton's Tables, Fifth Edition, 1811. Sine of 6° 8', for 1063425, read ⚫1068425. |