No. SATURDAY, February 12. 1780.

Ex fumo dare lucem

Cogitat, ut fpeciofa dehinc miraculo promat. HOR.

A

UTHORS have been divided into two claffes, the inftructive 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 thefe departments is there, in modern writing, much pretenfion to originality. In fcience, they fay, fo much has been already difcovered, that all a modern writer has left is, to explain and enforce the systems of our predeceffors; and, in literature, our fathers have fo exhausted the acuteness of reafoning, the flashes of wit, the luxuriance of defcription, and the inven tion 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 ftory.

However true this complaint may be in the main, there is one clafs of writers to whom the charge of tritenefs docs, 1 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 fcience, when every field was open to the refearches of industry,, and the invention of genius. The writers I allude to, are the authors of thofe 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 clafs 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 difeafe was an evil which mankind had inherited as a punifhment for the lapfe of their progenitor. Milton has given, in his Paradife Loft, a catalogue of some of thofe 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 difcovery, has informed us, that, in his treatment of thofe diforders, there is no evil, no pain, but, on the contrary, much pleasure, and even luxury. "I engage," fays 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 foften and relax the too hard "and dry mufcular and nervous fibres, and "contracted ligaments; and to harden and make

compact, and give the proper tone and elasticity to the too moist and flabby muscular and "nervous fibres and relaxed finews, and pro"vide and establish an equilibrium between the "fluids and veffels; to fweeten acrid, corrofive, "and faline humours; and to cure the dropfy,

afthma, confumptions, colic, gravel, rheu"matism, palsy, pleurify, and fevers, fonė "and gout, fcurvy and leprofy; to mollify and "and destroy inveterate callofities, to deterge "and cure obftinate ulcers, &c.

"These are not the reprefentations of a "Quack's bill; I deteft the arts of quackery as "much

"much as any man living. I deal not in no"frums or myfteries, or magic or expedient to captivate:

"Non fibi, fed toto genitum fe credere mundo."

If he who invented one new pleasure was formerly thought intitled to imperial munificence, what reward does the Doctor deferve who has added as many luxuries to the lift as there are difeafes 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 ftores of natural hiftory the following very curious facts, with regard to the properties of air and heat. Mr Fair, mafon, oppofite to the White-Hart Inn, Grafs Market, Edinburgh, thus delivers himself on the fubject of pneumatics. "Air and Smoke," fays he, "are "two elaftic fluids, capable of being condenfed "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 fmoke 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 mafon in finishing of the fire-places. "On the contrary, it is the caufe of fmoke."

"The other caufe of fmoke is the wind. Wind is a current of the air always rushing into "voids. At the fame time it goes forward by "the law of gravity, it has a tendency to "press downwards. Now, when it blows over "6 any one object higher than the chimney-top, "gravity brings it downward, pressing the "Smoke before it."

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

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

time;