XXXVI

INTRODUCTION.

have no hesitation in believing, is the most complete of any inthe United States , and by far the most extensive,* is so regulated,that each section of a class regularly recite, and are interrogatedon each subject of instruction, so that, while an emulation to excelis thus excited, the comparative merit or standing of the cadets isthereby determined. Adopting the same system in the Chemicaldepartment, that of interrogation on the subject of the precedinglecture, has many peculiar advantages; so that, while the mindand memory of the pupil are thus exercised, a comparative esti-mate of the progress of each one is obtained during each week,by which we are enabled, as in other departments, to present aWeekly Class Report of their progress.

While we are indebted to the talents and industry of the pro-fessors and teachers of the Academy , for the flourishing conditionit is now in, and the progress of the cadets in every branch theretaught; it is but justice to remark, that for the present organiza-tion of the academy, as relates to the. studies, which is obviouslypreferable to the old system, and also for the improvements ininstruction, we are indebted to the present superintendent, Col. S.Thayer, of the U. S. corps of engineers.

Considering pyrotechny, abstract from the questions usuallygiyen, and forming a distinct branch, it may be proper to remark,that the interrogatories on this head have been minutely and satis-factorily answered. The following outline will exhibit the order inwhich such questions were put, observing, however, that they aremerely in connection with this subject:

What is saltpetre? What is nitric acid? What is potash? Whatare the sources of saltpetre, and how is it obtained? How is itformed in nitre beds, extracted, and refined? What circumstan-ces are necessary to produce nitre, and how does animal matteract in its production? What is the difference between the old andnew process for refining saltpetre? What reagents are used todiscover the presence of foreign substances in nitre? What arenitre caves? Where do they exist? What are the nitre caves of the

* Of this fact the reader may form some idea, when he is informed, thatNewton’s Principia, Biot’s Physique, Hatchette, Gregory, &c. &c. formthe class books of instruction, works which require deep study, and pro-found thought.