To illustrate one thing by its resemblance to another, has been always the most popular and efficacious art of instruction. There is indeed no other method of teaching that of which any one is ignorant, but by means of something already known; and a mind so enlarged by contemplation, and inquiry, that it has always many objects within its view, will seldom be long without some near and familiar image through which an easy transition may be made to truths more distant and obscure.

Of the parallels which have been drawn by wit and curiosity, some are literal and real, as between poetry and painting, two arts which pursue the same end, by the operation of the same mental faculties, and which differ only as the one represents things by marks permanent and natural, the other by signs accidental and arbitrary. The one, therefore, is more easily and generally understood, since similitude of form is immediately perceived; the other is capable of conveying more ideas, for men have thought and spoken of many things which they do not see.

Other parallels are fortuitous and fanciful, yet these have sometimes been extended to many particulars of resemblance by a lucky concurrence of diligence and chance. The animal body is composed of many members, united under the direction of one mind: any number of individuals, connected for some common purpose, is therefore called a body. From this participation of the same appellation arose the comparison of the body natural and body politick, of which, how far soever it has been deduced, no end has hitherto been found.

In these imaginary similitudes, the same word is used at once in its primitive and metaphorical sense. Thus health, ascribed to the body natural, is opposed to sickness; but attributed to the body politick stands as contrary to adversity. These parallels therefore have more of genius, but less of truth; they often please, but they never convince.

Of this kind is a curious speculation frequently indulged by a philosopher of my acquaintance, who had discovered, that the qualities requisite to conversation are very exactly represented by a bowl of punch.

Punch, says this profound investigator, is a liquor compounded of spirit and acid juices, sugar and water. The spirit, volatile and fiery, is the proper emblem of vivacity and wit; the acidity of the lemon will very aptly figure pungency of raillery, and acrimony of censure; sugar is the natural representative of luscious adulation and gentle complaisance; and water is the proper hieroglyphick of easy prattle, innocent and tasteless.

Spirit alone is too powerful for use. It will produce madness rather than merriment; and instead of quenching thirst will inflame the blood. Thus wit, too copiously poured out, agitates the hearer with emotions rather violent than pleasing; every one shrinks from the force of its oppression, the company sits entranced and overpowered; all are astonished, but nobody is pleased.

The acid juices give this genial liquor all its power of stimulating the palate. Conversation would become dull and vapid, if negligence were not sometimes roused, and sluggishness quickened, by due severity of reprehension. But acids unmixed will distort the face and torture the palate; and he that has no other qualities than penetration and asperity, he whose constant employment is detection and censure, who looks only to find faults, and speaks only to punish them, will soon be dreaded, hated and avoided.

The taste of sugar is generally pleasing, but it cannot long be eaten by itself. Thus meekness and courtesy will always recommend the first address, but soon pall and nauseate, unless they are associated with more sprightly qualities. The chief use of sugar is to temper the taste of other substances; and softness of behaviour, in the same manner, mitigates the roughness of contradiction, and allays the bitterness of unwelcome truth.

Water is the universal vehicle by which are conveyed the particles necessary to sustenance and growth, by which thirst is quenched, and all the wants of life and nature are supplied. Thus all the business of the world is transacted by artless and easy talk, neither sublimed by fancy, nor discoloured by affectation, without either the harshness of satire, or the lusciousness of flattery. By this limpid vein of language, curiosity is gratified, and all the knowledge is conveyed which one man is required to impart for the safety or convenience of another. Water is the only ingredient in punch which can be used alone, and with which man is content till fancy has framed an artificial want. Thus while we only desire to have our ignorance informed, we are most delighted with the plainest diction; and it is only in the moments of idleness or pride, that we call for the gratifications of wit or flattery.

He only will please long, who, by tempering the acidity of satire with the sugar of civility, and allaying the heat of wit with the frigidity of humble chat, can make the true punch of conversation; and, as that punch can be drunk in the greatest quantity which has the largest proportion of water, so that companion will be oftenest welcome, whose talk flows out with inoffensive copiousness, and unenvied insipidity.