Let it be deeply impressed, and frequently recollected, that he who has not obtained the proper qualifications of an author, can have no excuse for the arrogance of writing, but the power of imparting to mankind something necessary to be known. A man uneducated or unlettered may sometimes start a useful thought, or make a lucky discovery, or obtain by chance some secret of nature, or some intelligence of facts, of which the most enlightened mind may be ignorant, and which it is better to reveal, though by a rude and unskilful communication, than to lose for ever by suppressing it. But few will be justified by this plea; for of the innumerable books and pamphlets that have overflowed the nation, scarce one has made any addition to real knowledge, or contained more than a transposition of common sentiments, and a repetition of common phrases. It will be naturally inquired, when the man who feels an inclination to write, may venture to suppose himself properly qualified; and, since every man is inclined to think well of his own intellect, by what test he may try his abilities, without hazarding the contempt or resentment of the publick. The first qualification of a writer is a perfect knowledge of the subject which he undertakes to treat; since we cannot teach what we do not know, nor can properly undertake to instruct others while we are ourselves in want of instruction. The next requisite is, that he be master of the language in which he delivers his sentiments: if he treats of science and demonstration, that he has attained a style clear, pure, nervous, and expressive; if his topicks be probable and persuasory, that he be able to recommend them by the superaddition of elegance and imagery, to display the colours of varied diction, and pour forth the musick of modulated periods. If it be again inquired, upon what principles any man shall conclude that he wants those powers, it may be readily answered, that no end is attained but by the proper means; he only can rationally presume that he understands a subject, who has read and compared the writers that have hitherto discussed it, familiarized their arguments to himself by long meditation, consulted the foundations of different systems, and separated truth from errour by a rigorous examination. In like manner, he only has a right to suppose that he can express his thoughts, whatever they are, with perspicuity or elegance, who has carefully perused the best authors, accurately noted their diversities of style, diligently selected the best modes of diction, and familiarized them by long habits of attentive practice.