Experiments and Observations on Different Kinds of Air. Joseph Priestley

as he had very little knowledge of air, so he had few doubts concerning it. Had Dr. Hales, after his various and valuable investigations, given a list of all his desiderata, I am confident that he would not have thought of one in ten that had occurred to me at the time of my last publication; and my doubts, queries, and hints for new experiments are very considerably increased, after a series of investigations, which have thrown great light upon many things of which I was not able to give any explanation before.

      I would observe farther, that a person who means to serve the cause of science effectually, must hazard his own reputation so far as to risk even mistakes in things of less moment. Among a multiplicity of new objects, and new relations, some will necessarily pass without sufficient attention; but if a man be not mistaken in the principal objects of his pursuits, he has no occasion to distress himself about lesser things.

      In the progress of his inquiries he will generally be able to rectify his own mistakes; or if little and envious souls should take a malignant pleasure in detecting them for him, and endeavouring to expose him, he is not worthy of the name of a philosopher, if he has not strength of mind sufficient to enable him not to be disturbed at it. He who does not foolishly affect to be above the failings of humanity, will not be mortified when it is proved that he is but a man.

      In this work, as well as in all my other philosophical writings, I have made it a rule not to conceal the real views with which I have made experiments; because though, by following a contrary maxim, I might have acquired a character of greater sagacity, I think that two very good ends are answered by the method that I have adopted. For it both tends to make a narrative of a course of experiments more interesting, and likewise encourages other adventurers in experimental philosophy; shewing them that, by pursuing even false lights, real and important truths may be discovered, and that in seeking one thing we often find another.

      In some respects, indeed, this method makes the narrative longer, but it is by making it less tedious; and in other respects I have written much more concisely than is usual with those who publish accounts of their experiments. In this treatise the reader will often find the result of long processes expressed in a few lines, and of many such in a single paragraph; each of which, if I had, with the usual parade, described it at large (explaining first the preparation, then reciting the experiment itself, with the result of it, and lastly making suitable reflections) would have made as many sections or chapters, and have swelled my book to a pompous and respectable size. But I have the pleasure to think that those philosophers who have but little time to spare for reading, which is always the case with those who do much themselves, will thank me for not keeping them too long from their own pursuits; and that they will find rather more in the volume, than the appearance of it promises.

      I do not think it at all degrading to the business of experimental philosophy, to compare it, as I often do, to the diversion of hunting, where it sometimes happens that those who have beat the ground the most, and are consequently the best acquainted with it, weary themselves without starting any game; when it may fall in the way of a mere passenger; so that there is but little room for boasting in the most successful termination of the chace.

      The best founded praise is that which is due to the man, who, from a supreme veneration for the God of nature, takes pleasure in contemplating his works, and from a love of his fellow-creatures, as the offspring of the same all-wise and benevolent parent, with a grateful sense and perfect enjoyment of the means of happiness of which he is already possessed, seeks, with earnestness, but without murmuring or impatience, that greater command of the powers of nature, which can only be obtained by a more extensive and more accurate knowledge of them; and which alone can enable us to avail ourselves of the numerous advantages with which we are surrounded, and contribute to make our common situation more secure and happy.

      Besides, the man who believes that there is a governor as well as a maker of the world (and there is certainly equal reason to believe both) will acknowledge his providence and favour at least as much in a successful pursuit of knowledge, as of wealth; which is a sentiment that entirely cuts off all boasting with respect to ourselves, and all envy and jealousy with respect to others; and disposes us mutually to rejoice in every new light that we receive, through whose hands soever it be conveyed to us.

      I shall pass for an enthusiast with some, but I am perfectly easy under the imputation, because I am happy in those views which subject me to it; but considering the amazing improvements in natural knowledge which have been made within the last century, and the many ages, abounding with men who had no other object but study, in which, however, nothing of this kind was done, there appears to me to be a very particular providence in the concurrence of those circumstances which have produced so great a change; and I cannot help flattering myself that this will be instrumental in bringing about other changes in the state of the world, of much more consequence to the improvement and happiness of it.

      This rapid progress of knowledge, which, like the progress of a wave of the sea, of sound, or of light from the sun, extends itself not this way or that way only, but in all directions, will, I doubt not, be the means, under God, of extirpating all error and prejudice, and of putting an end to all undue and usurped authority in the business of religion, as well as of science; and all the efforts of the interested friends of corrupt establishments of all kinds will be ineffectual for their support in this enlightened age: though, by retarding their downfal, they may make the final ruin of them more complete and glorious. It was ill policy in Leo the Xth to patronize polite literature. He was cherishing an enemy in disguise. And the English hierarchy (if there be any thing unsound in its constitution) has equal reason to tremble even at an air-pump, or an electrical machine.

There certainly never was any period in which natural knowledge made such a progress as it has done of late years, and especially in this country; and they who affect to speak with supercilious contempt of the publications of the present age in general, or of the Royal Society in particular, are only those who are themselves engaged in the most trifling of all literary pursuits, who are unacquainted with all real science, and are ignorant of the progress and present state of it.[1]

      It is true that the rich and the great in this country give less attention to these subjects than, I believe, they were ever known to do, since the time of Lord Bacon, and much less than men of rank and fortune in other countries give to them. But with us this loss is made up by men of leisure, spirit, and ingenuity, in the middle ranks of life, which is a circumstance that promises better for the continuance of this progress in useful knowledge than any noble or royal patronage. With us, politics chiefly engage the attention of those who stand foremost in the community, which, indeed, arises from the freedom and peculiar excellence of our constitution, without which even the spirit of men of letters in general, and of philosophers in particular, who never directly interfere in matters of government, would languish.

      It is rather to be regretted, however, that, in such a number of nobility and gentry, so very few should have any taste for scientifical pursuits, because, for many valuable purposes of science, wealth gives a decisive advantage. If extensive and lasting fame be at all an object, literary, and especially scientifical pursuits, are preferable to political ones in a variety of respects. The former are as much more favourable for the display of the human faculties than the latter, as the system of nature is superior to any political system upon earth.

      If extensive usefulness be the object, science has the same advantage over politics. The greatest success in the latter seldom extends farther than one particular country, and one particular age; whereas a successful pursuit of science makes a man the benefactor of all mankind, and of every age. How trifling is the fame of any statesman that this country has ever produced to that of Lord Bacon, of Newton, or of Boyle; and how much greater are our obligations to such men as these, than to any other in the whole Biographia Britannica; and every country, in which science has flourished, can furnish instances for similar observations.

      Here my reader will thank me, and the writer will, I hope, forgive me, if I quote a passage from the postscript of a letter