Big engineering schemes seem to be the order of the day, and the Pennsylvania Railroad Company is determined to keep imes Tudging from the devastation now being wrought by hovels and dynamite at frequent intervals betwoon Pittsburgh and Now York, one concludes that this great corporation has respect fo neither gods nor men. Excelsior is the motto, and no obstacles caused by geologi¢ elevations and depressions ars to be left unconquered where they stand in the way of the shortest route or easiest gradient for the great highway through the Alleghany 'Mountains. Long stretches of costly roadbed with bridges, cuts, and fills are being abandoned in favour of more costly cut offs: upon the principle that the best is cheapest. No other course is feasible in view of the enormous traffic' between New York and the West. Ona recent journey over the 235 miles fom Harrisburg to the Pitcairn yards east of Pittsburgh, I counted 54 east-bound freight trains of a thousand tons of cargo each: This, for a six hours' run, will afford som of the immense traffic handled every twenty-four hours. Frequently three trains. and: occasionally four trains are seen passing a given point, proving that the four-track. system is no merely ornamental feature of the line: All steel bridges are bring replaced by to uso the Slido-Rule. The Slide Ralo is no now instrument, though ite the present day is not commensurate its utility. The reason for this ably that the various text books hit published on the subject, whilom very thorough in their treatment of the priuciples of the Rule from the expert's point of view, do not commend themselves to a ner, and Mr, Tyler has happily couceived the idea of writing a paper from the point of view of one who han j tered' it, bec uso the difficulties unself experienced in learning: from other text books ure One of ylor in learn ing to uso the Slide Rule, is the difficulty in ascertaining the correct position of the decimal point in the rosult'of a calcula~ tion, and he proceeds to suggest a system which is certainly simpler and more readily grasped: and remembered than any published so far. Students who follow Mr. 'Tyler's method will be' in a bettor position than those who have failed to grasp the systems hitherto advocated and, consequently, have to rely upon "inspec tion" of the figures which enter into the problem. A feature of Mr. Tyler's paper is the concise way in which he gives muewouie figures for the calculation of squares, square roots, cubes, cuba roots, areas of circles, curved areas of cylinders, volumes of cylinders, direct Jogarithmic and trigonometrical process ses, etc., and those can all be inscribed ordinary Slide Rule without any difficulty.
The paper will form a part of the next volume of Proceedings of the local Socioty of Enginoers:& Architects, and noted that it is published for the information of younger members and students.
Text read from the printed page and cleaned; old type leaves the occasional error.