An Encyclopedia for Teenagers

We live in a century so enlightened that one must have a wealth of knowledge in order to be a so-called 'ordinary man'. One must be able to write tolerably well; possess several skills to a moderate degree of proficiency; and be able to appreciate many kinds of beauty. No longer are these traits remarkable. They are the fruit of education and prevailing fashion. Even if an education isn't entirely satisfactory to make one erudite, at least one must admit that it does produce people who are kind, and who have an unusual spirit. Besides, which is preferable: to enhance the spirit of society at the expense of profundity, or profundity at the expense of the spirit of society? These questions have always produced contrary feelings and the problem remains unresolved. If I dare venture my opinion, I would say that one kind of education suits certain individuals while another benefits a more general audience.

The scholar who buries himself in a library where he spends his life sifting through old manuscripts, has to make a system of chronology to delve below the images that time has stamped on the ancient centuries. He has to meditate on the ways in which nature operates to bring about its prodigies. Finally, he has to wonder whether the first principles of bodies are square, round, or triangular. This scholar can be a very useful individual indeed, but apart from the kind of specialized knowledge that he has received, he could be quite ignorant. Take, for example, a jurist who has the comedy of St. Aideurs confused with a touching tragedy, and who is unable to differentiate between the little dogs of Sintisme and the main characters. Or, witness the geometry expert who, after reading an interesting poem, says naively "So, what does it prove?" These people certainly cannot speak meaningfully about anything besides jurisprudence and geometry, and this places them inside a rarefied spiritual circle.

The book that I propose is a compendium of human knowledge far removed from anything that might make for unpleasant reading. It is a distillation of an infinite number of excellent books, English and French. It is an extract of a multitude of interesting articles from the Encyclopedia. It is a survey of the arts and sciences which can be useful to a person who is already knowledgeable, but it is mainly intended to provide the rudiments for those who may be entering their sanctuary for the first time. It also satisfies those who just want a clear and general overview.

Young people lack a book of elementary but universal knowledge in which they can draw understanding with a minimum of difficulty. Under the discipline of classes and a teacher some people detest studying, therefore little benefit can be expected from it unless there is some degree of freedom. So, for young people there must be an abridgement, but this condensed version must still contain the essence that will further their development. An abstract, if it is well done, is the spiritual outline of a larger tableau. First we are introduced to a rough outline of a subject. Then through sampling and tasting we enlarge our understanding until we finally see it in a state of perfection, having neglected nothing. In the same way that many sketches can eventually turn one into a painter, so a lot of extracts can eventually turn one into an educated man.

There are already some books that appear under the name of Basics of Science, but until now these have been defficient. Some suffer for a lack of order, while others by their lack of interesting material. Some authors, forgetting that they are speaking to adolescents, use technical terms exhaustively without bothering to define them. They don't realize that this only serves to obscure rather than clarify. On the other hand some say too much while others don't say enough. For instance, with regards to morals and history (which one cannot learn simply through extracts), and geography - these subjects are omitted entirely as of little importance. I dare say that my perspective is better, however I cannot be the judge because that ultimately is something for the public to decide.


The Origin of Things - We pass in review the various opinions of ancient philosophers on the formation of beings. The three systems of Monsieur Buffon regarding the origin of things, the theory of the earth, the reproduction of organized beings with an attached extract of his excellent discourse which compares animals and plants.

Theology - Its origin, its definition, its different meanings, its divisions.

Philosophy - We define this science taken in its general sense, and then treat it separately in its 4 branches which are the logical, moral, physical, and metaphysical.

Mathematics - We touch upon all types of arithmetic and give an idea of algebra, comparing it with ordinary arithmetic by way of a few problems solved both ways. Upon analysis we see its superiority over calculations made numerically. There are discussions on geometry, planes, surfaces, solids, conical sections, practical geometry, combinations, permutations, and this science is presented in such a way as to educate as well as to say enough for those who simply want to have a general idea.

Astronomy - We recount the origin of this science. We introduce the various systems with comments on each. We discuss the sun and its activity, and provide a way that anyone can use to calculate its diameter. We examine the relative spacing of planets according to the system devised by Copernicus, then we determine their respective distances using trigonometry. We see how the seasons arise from the earth's obliqueness to the sun; we discuss the moon, eclipses, comets, and finish with a general view of the universe.

Gnomonics - We define this science and give the names of its different sections; then we outline the way to determine verticals and horizontals by a very simple method. [This science involves placing right-angles on the surface of a sphere. This knowledge involving spherical trigonometry is essential to those who make sun dials.]

Navigation - How to determine one's location and how to estimate the course of a vessel by the means devised by Loetz; how important it is to know the exact time in determining one's longitude; we recount the origin of this science and its progress; we mention the era in which the compass was discovered and see the benefits that have resulted from it.

Chronology - Like Gnomonics and Navigation, this is another child of Astronomy. We look at the different systems of chronology and show that since the creation up to the time of Jesus Christ, there is among chronologists a difference of 2984 years; according to the Hebrew text Shem lived to be 302 and Noah was 350 years after the flood, consequently they were able to see their children establish the nations; slaughter each other; and to cry, 'Stop! You are brothers!'; that Abraham was a contemporary of Noah; and that Samuel survived Isaac by 30 years. We close with a look at certain notable eras.

Tables - We explain tables involving the number of gold, elements, the solar cycle, the dominical letter, and give ways of making these calculations for things that lend themselves to the primary elements of arithmetic.

Mechanics - We discuss mechanics - speculative and rational; we mention levers and then explain each type through everyday examples used by everyone; we contemplate machines in general such as the screw, the winch, capstan, inclined plane, and give an idea of the great advantage that may result from their use.

Statics - We establish the principles of this science; we mention the dropping of a body; its acceleration while falling; the various kinds of statics, varying speeds and things related to it.

Hydraulics and Hydrostatics - We consider the pressure of fluids and the weight of other bodies pressing down on them; these are then compared with what happens with solids; it deals with homogeneous or similar fluids and heterogeneous or dissimilar fluids; we provide a way to make sense of the infinite number of phenomena that present themselves in these two sciences with reference to things that happen each day before our very eyes.

Optics - We consider the laws by which light rays depart from a luminous point and come to the eye; we demonstrate why the same objects can appear large or small; we discuss illusions (mirages) as errors in viewing, etc.

Dioptrics - This establishes the principles of reflection and refraction of light rays; we adapt this refraction to the stars where they seem to appear where they are not; we discuss spectacles, telescopes, microscopes, and we finish with a short course on how to use a microscope.

Catoptrics - In which we discuss mirrors that are flat, concave and convex, and the different images that they produce.

Perspective - We define its various branches and give some rules relative to paintings which are sufficient to make one understand works of art.

Architecture - We consider its different aspects by examining its 5 orders [Ionic, Doric, etc.]; we note their unique signs and characteristics; and we give a way to reliably identify them so as not to be fooled by those who have rendered their judgment of various edifices.

Acoustics - This science deals with sound; we define it and consider its different aspects.

Different Materials - In this section we discuss the qualities of materials taken separately: composition; expansion; forces; solidity; ductility; motion; weight or pressure; lightness; attraction; consistency; density; scarcity; stiffness; flexibility; elasticity; fluidity; temperature; odour; color; light; sound; wind; rain; snow; hail; ice; meteors; rainbows; clouds; sun dogs; aurora borealis; thunder; lightning; tides; the different strata of the earth; volcanoes; earthquakes; fossils; minerals; metals; rocks; electricity; magnetism; vibrations; phosphors, cohesion, etc. Each of these items is dealt with separately.

Introduction to Geography - This explains all the terms used in geography, including those pertaining to spheres.

Geography - This part is complete enough to form a good geographer in a social setting.

Ancient Geography - This interesting section has been added to promote awareness of its history; it is important to know where Thebes, Corinth, and Babylon were, etc.

Use of the Terrestrial Globe - We show how a globe can be used to solve problems such as finding the latitude and longitude of a given place; determining the distance between two places; finding the antipodes; on a given day and time of year to say where the sun is directly overhead, and how to determine the time of sunrise and sunset; and we added the description of a sphere; we also mention the use of the celestial sphere.

History - Since you cannot learn history by way of extracts, we are content to provide a dissertation by which the following can be read fruitfully.

Natural History - We provide a short discussion on this science, and the way to study it, according to the views of Mr. Buffon.

Eloquence - We copied this article by Mr. Voltaire from an Encyclopedia.

Rhetoric - All aspects of this science are reviewed with examples taken from the best authors; we consider various unwieldy terms replaced by synonyms so as not to tax the mind unnecessarily.

Poetry - We make known all the genres with examples, and we end with rules on versification.

Military Arts - We develop succinct principles, and we introduce all the branches that are connected with it.

Medicine - We consider its origin, followed by its progress, and discuss in detail its five parts which includePhysiology or knowledge of the human body for the purpose of its care; Pathology or knowledge of the human body when in a state of illness; Semeiotics which compiles the signs of sickness and health; Hygiene which prescribes the appropriate regime to retain good health; and Therapeutics which teaches the practical remedial arts.

Botany - Its purpose; its divisions; general description of a plant; sentiments of botanists on vegetation; the uses of plant material; their diseases, etc.

Chemistry and Alchemy - We describe the objects of the two sciences; we separate the 3 fields; we analyse the body and consider the application of chemistry and medicine to the body; to the military arts; to natural philosophy; how to distinguish true alchemy from false alchemy; and how to put readers on guard against the bad faith of hucksters by their dissemination of a few facts.

Jurisprudence - Which is knowledge of the rules applied in each country to exercise justice; it details the qualities that a jurist must have; we look at the different kinds of law and their peculiarities.

Music - We discuss the sound emanating from a resonating body; principles of melody and harmony; we deal with modalities and study their origin; intervals; chords; we learn the effect of their reversals; and talk about the different genres of music; keys; movements; measures; transposition; and we end with an abstract on the system of Mr. Bousseau to perfect the art of musical notation.

Painting - We recount its origin; follow its progress; appreciate its benefits; ascertain the qualities that characterize a good painter; provide principles for all the different ways to paint; the art of fixing pastel; a practical way by the author to give him force in oils and to do things which this genre normally does not lend itself to; one will again discover the way to make carmine.

Sculpture - We compare its parallels to painting; note the qualities of a sculpture; discover the pitfalls of this art; and we mention beautiful ancient productions.

Engraving - We ponder its antiquity; we pass in review all the ways to engrave and the means employed in each method; and we finish with anecdotes about the most famous of the ancient engravers.

Printing - its origin; the cities that are competing for the glory of having given birth to printing; the names of the different people who are considered to be its inventors; the first printed works; famous printers; we end up by conducting the reader through a print shop and introducing him to all its operations.

Mythology - We are shown the usefulness of this science, bizarre though it may be; it deals with the gods and goddesses; their attributes; the muses; graces; demons; sylvan deities; fountains; rivers; flowers and mountains; hell; elysian fields; the furies; the Trojan war; the conflict in the formation of man; the seasons; giants; and finally the metamporphosis following the order established by Ovide.

Heraldry - We explain the emblems; symbols; figures of the coat-of-arms; honourable pieces; the connection that livreys must have with the arms, crowns, helmets, etc. and we close with the nomenclature of heraldic terms in alphabetical order.

The Seven Wonders of the world - We explain what the 7 Wonders were, which are so often referred to without really knowing what they are.

Foreign Exchange - We establish the relationship between currencies; we show how it operates to reduce the value of foreign money when it is exchanged for French currency, and vice versa, when French money is exchanged for foreign currency.

Various Amusements - We pose informative and enjoyable problems that can be solved through simple means; one engages in a short course of easy experiences on different branches of physics; there are tours of maps; one earns points and penalties, etc.; one learns how to obtain equal measures of quantities in separate vases; to determine the height of an object by its shadow or by its reflection; to get a rough measure of a distant object using the tip of one's hat; and we close with a few secrets - some that are useful, and others that are just for fun.

Such is the plan of the author in a nutshell. In order to avoid a much longer description, an infinite number of other interesting items set in appropriate places have been omitted. His purpose isn't to immerse young people in all the sciences because this is impossible within the space of two volumes of 500 pages each, but he hopes to introduce subjects which they can embrace and show the way in which their goals can be attained. May it serve to whet their appetite!

[The topics proposed above are reflected in the General Index of the Encyclopedia that Isaac eventually produced.]

Isaac's initial proposal to the Academy of Sciences, Arts and Belles Lettres at Dijon, France,
repository of Isaac Crommelin's research papers. Images taken in September, 2008 by Govert Deketh.