Rulars Jano 16-42

PREFACE.

I AM publishing the following notes because I think they may possibly supply the want of a Field-book,-a want which I have often felt myself and have often heard expressed— which, while avoiding as much as possible the intricacies of mathematics, would be of more general application than any of the books of this class which I have as yet come

across.

The Railroad engineer is rarely an expert mathematician : in fact it has always seemed to me that the time which must necessarily be spent by him in attaining mathematical proficiency might be very much better employed in reading up some of the more practical subjects, of his profession. Bearing this in mind, I have endeavored to strip the following pages of all unnecessary mathematical deductions, making it mainly my object to give the results deduced, and yet at the same time giving sufficient explanation to enable any one possessed of the ordinary smattering of mathematics and mechanics to deduce the same results for himself.

I have avoided the insertion of Logarithmic Tables. I am well aware that to some this will appear a serious omission; but considering that this is merely a Field-book, and not a work to be consulted in cases where accuracy in the 6th figure is usually essential, I have deemed that the exclusion of the hundred pages or so which this omission permits, amply compensates for the few seconds of additional labor which the lack of them may occasionally involve. Speaking for myself, as regards Railroad work, I must say that for one time that I work by logarithms I work a hundred times by "naturals;" and I know that most engineers would bear similar testimony. In the Astronomical problems in the latter part of the book, considerable labor may, of course, be saved by the use of