We have thus, in this brief and hasty outline of the nature, principal effects, and properties of caloric, detailed the leading facts on this subject; from which it will be seen, that caloric, so far as respects its generation by the combustion of different pyro-mixtures, and effects, generally, should form a part of Pyrotechny, and claim the attention of those, who are connected with the preparation of Fire-Works.
Respiration is also a process which puts quiescent heat in motion.[5]
In the second part of the work, we embrace the furniture of a laboratory, for the use of fire-workers, consisting of various tools and utensils.
Under this head, we also embrace sundry manipulations, such as the preparation of substances for use, the manner of forming mixtures, and various anterior operations. The formation of pasteboard for cases, the mode of forming as well as charging cases, different modes of charging rockets, the dimensions of rammers, mallets &c. This preliminary ought to be well understood; as the successful practice of the art depends greatly on these operations. We may observe, however, that we have had occasion to repeat some of these manipulations in certain instances, to make them more intelligible; or rather to present, more in connection with the subject, a detail of minutiæ.
In the different compositions, the reader will bear in mind, that the copious collection of formulæ, both old and new, embraces all the facts, with which we are acquainted, concerning pyrotechnical preparations.
In most instances, where the importance of the subject required it, we designated, or set apart from the rest, formulæ, which have been approved, and particularly in France.
This is more particularly the case as it respects the fourth and last part, which appertains exclusively to Military Fire-Works. On this subject, permit me to remark, that fire-works, intended for the purposes of war, should be depended on; and for that reason, in order to produce a certain effect, the materials of which they are composed should be pure, weighed with accuracy in the proportions required, and carefully mixed according to the rules laid down. It is true, however, that while this nicety is required in particular cases, it is unnecessary in the formation of all fire-works. The composition for carcass and light-ball, for tourteaux, links, and fascines, and some others, do not require that precision; whereas the composition for fuses for bombs, howitzes, and grenades should be in every respect accurately made; for on the accuracy of the composition, must depend the time a fuse will burn, which is afterwards regulated by using more or less of the fuse, according to the time it will take for the shell to reach its destination, on which depends the skill of the bombardier. Accuracy, however, in making of preparations should be a general rule.
Viewing Pyrotechny either as a science or an art, there is undoubtedly required in its prosecution much skill and practice. A knowledge of the theory of fire-works may be readily acquired. The mere artificer or fire-worker, by constant habit and experience, may understand it is true how to mix materials, prepare compositions, charge cases, and perform all other mechanical operations; but it is equally certain, that, without a knowledge of chemistry, he cannot understand the theory. We would not say, that the workman should be a chemist, but that he should know enough to determine the purity of the substances he employs, and their respective qualities and effects; for if that principle were admitted, we might go further and say, that every person, who practices a chemical art, as the tanner, gluemaker, brazier, &c. should be a chemist, or that the art could not be conducted without a previous knowledge of chemistry, which we know is contrary to fact. This, however, may be said, that in all arts which are decidedly chemical, as that of dying for instance, chemical knowledge will enable the artist or operator to conduct his processes with better advantage, and correct any old routine, which is too often pursued, because it was handed down from generation to generation. Mr. Seguin in France facilitated the preparation of tanned leather, by adopting a new process altogether chemical. In a word, so far as chemistry is connected with the arts, and by which we explain the operations that take place, it is undoubtedly important; and with regard to Pyrotechny, it appears, in the way we have mentioned, to be indispensable. Chaptal (Elements de Chimie) observes, that the works of artificers frequently miscarry in consequence of their being unacquainted with the art.
In noticing this subject, we may be permitted to digress, while we state, that, being fully convinced of this truth, we have directed our labours in the Chemical Department of the United States' Military Academy to two distinct objects; viz. to theoretical and experimental chemistry, forming the first year's course, and chemistry in its application to the arts, manufactures, and domestic economy, constituting, along with mineralogy, the course of the second year. In addition to the usual applications, Pyrotechny, in the manner we have stated, and especially that branch which treats of military fire-works, has claimed our attention; and we have reason to believe, that this addition, to the usual course of chemical instruction, has considerably advanced the utility, especially to gentlemen designed for the army, of the application of chemistry.
The system of instruction adopted throughout the academy, in the different departments, (the plan of which may be seen in the new Army Regulations, article Military Academy), which, we have no hesitation in believing, is the most complete of any in the United States, and by far the most extensive,[6] is so regulated, that each section of a class regularly recite, and are interrogated on each subject of instruction, so that, while an emulation to excel is thus excited, the comparative merit or standing of the cadets is thereby determined. Adopting the same system in the Chemical department, that of interrogation on the subject of the preceding lecture, has many peculiar advantages; so that, while the mind and memory of the pupil are thus exercised, a comparative estimate of the progress of each one is obtained during each week, by which we are enabled, as in other departments, to present a Weekly Class Report of their progress.
While we are indebted to the talents and industry of the professors and teachers of the Academy, for the flourishing condition it is now in, and the progress of the cadets in every branch there taught; it is but justice to remark, that for the present organization of the academy, as relates to the studies, which is obviously preferable to the old system, and also for the improvements in instruction, we are indebted to the present superintendent, Col. S. Thayer, of the U. S. corps of engineers.
Considering pyrotechny, abstract from the questions usually given, and forming a distinct branch, it may be proper to remark, that the interrogatories on this head have been minutely and satisfactorily answered. The following outline will exhibit the order in which such questions were put, observing, however, that they are merely in connection with this subject:
What is saltpetre? What is nitric acid? What is potash? What are the sources of saltpetre, and how is it obtained? How is it formed in nitre beds, extracted, and refined? What circumstances are necessary to produce nitre, and how does animal matter act in its production? What is the difference between the old and new process for refining saltpetre? What reagents are used to discover the presence of foreign substances in nitre? What are nitre caves? Where do they exist? What are the nitre caves of the Western country, and how is nitre extracted from the earth? What proportion of nitre does the saltpetre earth of the nitre caves afford? What is the theory of the process for extracting saltpetre from nitrous earth, or nitrate of lime? What is sulphur? How is it obtained, and how is it purified for the manufacture of gunpowder? Of what use is sulphur in the composition of gunpowder? Does it add to the effective force of gunpowder? What is charcoal? What is the best mode of carbonizing wood for the purpose of gunpowder? What woods are preferred for this purpose? In the charring of wood, what part is converted into coal, and what gas and acid are disengaged? What is the use of charcoal in gunpowder? What is gunpowder? What are considered the best proportions for forming it, and what constitutes the difference between powder for war, for gunning, and for mining? How does the combustion of gunpowder take place? Can you explain why combustion takes place without the presence of a gaseous supporter of combustion, as gunpowder will inflame in vacuo? What are the products of the combustion of gunpowder? What gases are generated? To what is the force of fired gunpowder owing? What are the experiments of Mr. Robins on the force of gunpowder? How would you