N° 80. SATURDAY, February 12. 1780.

Ex fumo dare lucem Cogitat, ut fpeciofa dehinc miraculo promat. HOR.

A

UTHORS have been divided into two

classes, the instructive and the entertaining, to which has been added a third, whomix, according to Horace, the "utile dulci and are, in his opinion, intitled to the highest degree of applaufe.

Readers complain, that, in none of these departments is there, in modern writing, much pretenfion to originality. In science, they say, so much has been already difcovered, that all a modern writer has left is, to explain and enforce the systems of our predecessors; and, in literature, our fathers have so exhausted the acuteness of reasoning, the flashes of wit, the luxuriance of description, and the invention of incident, that an author now-a-days can only give new form, not matter, to his argument; a new turn, not thought, to his

epigram: epigram; new attitudes, not object, to his picture; new language, not fituation, to his story.

However true this complaint may be in the main, there is one class of writers to whom the charge of triteness does, I apprehend, very little apply. They are generally of the first fpecies mentioned above, who publish useful information to mankind; yet, in the last quarter of the 18th century, their information is often as new as if they had written in the infancy of art and of science, when every field was open to the researches of industry, and the invention of genius. The writers I allude to, are the authors of those little effays which appear in the learned world under the title of ADVERTISEMENTS.

The neceffary and ornamental arts of life are equally the objects of the class of authors whom I defcribe. In both, I will venture to affert, that the novelty of their productions is equal to their usefulness.

It was formerly imagined, that disease was an evil which mankind had inherited as a punishment for the lapse of their progenitor. Milton has given, in his Paradise Loft, a catalogue of fome of those tormenting maladies

which were to be felt by the race of fallen Adam. So has Dr Dominiceti in an advertisement, which is now lying before me; but, with the most extraordinary force of original discovery, has informed us, that, in his treatment of those diforders, there is no evil, no pain, but, on the contrary, much pleasure, and even luxury. " I engage," says the Doctor, " with pleasure, and even luxury, to the "patient, to increase or diminish the vital heat, “ and the circulatory, fecretory, and excretory "functions; to soften and relax the too hard " and dry muscular and nervous fibres, and " contracted ligaments; and to harden and make “ compact, and give the proper tone and elasti" city to the too moist and flabby mufcular and " nervous fibres and relaxed finews, and pro“ vide and establish an equilibrium between the " fluids and veffels; to sweeten acrid, corrofive, " and faline humours; and to cure the dropsy, "asthma, consumptions, colic, gravel, rheu"matism, palsy, pleurisy, and fevers, stone " and gout, fcurvy and leprosy; to mollify and "and destroy inveterate callofities, to deterge " and cure obstinate ulcers, &c.

These are not the representations of a Quack's bill; I detest the arts of quackery as " much "much as any man living. I deal not in no"strums or mysteries, or magic or expedient to "captivate:

"Non fibi, sed toto genitum se credere mundo."

If he who invented one new pleasure was formerly thought intitled to imperial munificence, what reward does the Doctor deserve who has added as many luxuries to the list as there are diseases in the catalogues of nofology ?

Our own country has the honour of producing an author, who, in an advertisement published not long ago, has added to the stores of natural history the following very curious facts, with regard to the properties of air and heat. Mr Fair, mafon, opposite to the White-Hart Inn, Grafs Market, Edinburgh, thus delivers himself on, the fubject of pneumatics. Air and Smoke," says he, "are "two elastic fluids, capable of being condensed "and expanded. Heat, or the fire in the "grate, expands the air. Being expanded, "it becomes lighter. And, as it is in nature "for light matter to swim to the top of heavier, "it rifes up the vent, carrying the smoke a"long

"long with it. This is the principle by which "fire burns, and smoke afcends. Now, that "the particles of air may be brought above the "fire, that they may be heated to expand and "carry off the smoke, should be the chief care " of a mason in finishing of the fire-places. "On the contrary, it is the cause of smoke."

"The other cause of smoke is the wind. Wind " is a current of the air always rushing into "voids. At the same time it goes forward by "the law of gravity, it has a tendency to "prefs downwards. Now, when it blows over

any one object higher than the chimney-top, "gravity brings it downward, preffing the "Smoke before it."

It will be obferved, that, like many other great theorifts, Mr Fair uses a language in fome places a little obfcure; and that, in others, as where he mentions the tendency of wind to press downwards, his expreffion borders on the jocular; a liberty in which fome of the greatest philosophers have frequently indulged.

These discoveries, however new and aftonishing, are not fupernatural. But I have just now read an advertisement, which carries its information beyond the bounds of Space and