Excerpt from The Steam Engine and Gas and Oil Engines: A Book for the Use of Students Who Have Time to Make Experiments and Calculations
This is a book for students who have time to work many exercises. Almost every table of numbers is supposed to be worked out by the reader himself, or if he is supposed to verify only some of the numbers he must use the table in working other exercises. As an example of what I mean, consider Chap. III., in which a student is supposed to work out every number. If he is a beginner who knows but little mathematics he will work on squared paper, and he is led gradually through his own work to see, not only the value of expansion but the limit to its value because of back pressure and condensation; he sees for himself also the nature of the Willans Law. But the very same work ought to be done by an advanced student, only he will probably use formul? which he can prove to be correct, instead of squared paper. Now the knowledge conveyed in this simple manner is of the very greatest importance, but it is usually assumed that no beginner can take it in. Indeed I may say that advanced students have usually only a very vague comprehension of this kind of knowledge. There is all the difference in the world between an attempt to study by mere reading and a real study through the actual doing of work.
Readers have great faith. Tell them that some philosopher obtained a certain law of adiabatic expansion of steam and they use that law, never testing it for themselves, although the test may only need half an hour's work. Tell them that there is a method used by everybody for showing the wetness of the steam in a cylinder, on the indicator diagram, and they use that method, although the exercise of a little common-sense would show them that the method is based on a fallacious assumption.
About the Publisher
Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works. Это и многое другое вы найдете в книге The Steam Engine and Gas and Oil Engines (John Perry)