RHETORIC AND BELLES-LETTRES. 



been fully mastered. Scientific acquisition is a 

 work of severe discipline ; and the simplest steps 

 should be securely fixed before any attempt is 

 made to go beyond them. The art of the teacher 

 lies wholly in attending to this. The greater 

 number of the abstract sciences fall properly to 

 be taught by the schoolmaster, and not by unas- 

 sisted books. But when it is desired to make 

 science possessible by a reader going through a 

 book at an ordinary pace, the following procedure 

 must be adopted : 



1. The propositions or abstract notions must be 

 stated in the clearest possible form. 



2. Each proposition may be expressed in two 

 or three various forms of language, but there should 

 be some one form adopted for remembering it by. 

 A vivid epigrammatic statement of a proposition, 

 either before, or to sum up and condense, the 

 exposition, is always very effective, and indeed 

 necessary for the sake of the memory. 



3. It being understood that only one proposition 

 or abstraction is stated at a time, each must be 

 followed up by a series of examples or instances 

 chosen from things familiar to the reader. The 

 examples at first should be extremely simple, but 

 in the end they should become more difficult, so 

 as to shew the power of the principle to throw 

 light upon them. 



4. Besides explaining by examples or cases in 

 point, we may explain by illustration, or by similes 

 or parallels, from some class of subjects more 

 palpable to the understanding than the one treated 

 of; as when we illustrate the conflict of motives 

 in an individual mind by the visible contests of 

 animal strength. The caution in the use of illus- 

 trations is to see that they do not bring in con- 

 fusing ideas. 



The writer of a manual for schools, or of such a 

 book as Euclid's Elements, gives a whole string 

 of definitions, containing strange and unfamiliar 

 notions, without the slightest pause ; but the 

 popular writer must take care to bring upon the 

 stage only one new notion, or technical phrase, 

 at a time ; and each must be spread out, repeated, 

 exemplified, and illustrated, by easy exposition, 

 before the writer ventures upon a second. One 

 of the great burdens and pains of human life is to 

 work with half knowledge or half capacity ; and 

 this is never more felt than with the reader of a 

 scientific book, where novel conceptions flow in 

 upon him faster than he can fix them. 



It has been thought that the concrete objects of 

 the world are not sufficiently kept before the mind 

 in abstract expositions. This is true to a certain 

 extent ; for the doctrines of addition, subtraction, 

 multiplication, &c., and the theory of decimal 

 notation, which is the entire foundation of arith- 

 metic, might be rendered much more intelligible 

 by the use of objects such as wooden cubes 

 made up into rows and squares. This method 

 has been carried out in the system of Pestalozzi. 

 On the other hand, the necessity there is for 

 creating ciphers, symbols, and other artificial ap- 

 paratus, shews that we are committed to a peculiar 

 region of things ; and we must make up our minds 

 to comprehend and use the abstractions them- 

 selves, independently of the concrete forms. In 

 the most popular scientific book of our day, Dr 

 Arnott's work on Physics, where concrete illustra- 

 tion is carried as far as it has ever been in an 

 abstract exposition, the author, instead of proceed- 



ing gradually from the concrete to the abstract, 

 finds that the nature of his subject requires him 

 to place at the very threshold the four most ab- 

 stract notions that his subject contains namely, 

 atom, inertia, attraction, repulsion ; and he calls 

 upon his reader to comprehend these, as a pre- 

 liminary to all the rest 



In the other class of sciences such as Natural 

 History, Geography, Morals, &c., which, instead 

 of being universal and theoretical in their subjects, 

 are more or less either local or practical a differ- 

 ent style of treatment is possible. In the ex- 

 position of these there are two great maxims 

 never to be lost sight of : 



1. In endeavouring to make the reader compre- 

 hend a class of objects of animals, trees, shrubs, 

 rocks, strata, or whatever else it is essential to 

 fix the attention first upon some one actual speci- 

 men, and to describe it on all sides, with such a 

 degree of explicitness and fulness, that the entire 

 object shall be completely familiar to his mind. 

 This being once done, other individuals can be 

 defined and made known by their differences from 

 the typical one ; and whole classes can be chalked 

 out and discriminated. If one individual has been 

 thoroughly conceived in all its parts, then every 

 other individual may be conceived with the same 

 fulness when its difference is made known. Thus 

 the knowledge of the vertebrate series of animals 

 is best secured by a profound acquaintance with 

 the human anatomy : this once achieved, it requires 

 only an attention to the points of distinction to 

 have an equally profound and thorough acquaint- 

 ance with every individual of the vast series. Now 

 that a universal nomenclature has been completed 

 by the labours of Professor Owen, such a transition 

 from the human type to the vertebrate series is 

 rendered a comparatively easy task. But the 

 grasp of the whole will never be secure unless the 

 knowledge of the typical instance is certain. 



2. In bringing before us some object that can 

 be represented only by a series of descriptive 

 references to other things, it is necessary to com- 

 mence with the known, and proceed by known con- 

 nections to body forth the unknown. The exact 

 state of mind^ in respect to knowledge, and inter- 

 est or likings of the person addressed, must be 

 clearly kept in view. The interest of a description 

 increases by the number of ways that it connects 

 itself with our personal experience. Thus, to 

 describe a manufacturing process say the manu- 

 facture of soda the method is to commence it at 

 the stage where the hearer is familiar with the 

 things employed namely, at the employment of 

 sea-salt and oil of vitriol and then give every 

 successive action in language that recalls familiar 

 objects. 



The description of animals is rendered intelli 

 gible and interesting by dwelling upon the points 

 that have a parallel in human life ; as where they 

 get their living, how often they eat, when they 

 sleep, how they spend their day, the length of their 

 life, their hardships and difficulties, their pairing, 

 procreation, and parental solicitudes, their facul- 

 ties and capacities, their means of defence and 

 offence. The vegetable and mineral world has an 

 interest by relation to human uses and wants, as 

 well as to the uses of the animal creation at large. 

 If there is any animal or vegetable familiar to u 

 such as our household quadrupeds and insects 

 the naturalist has a good hold on our attention, 



