Produced by Mark C. Orton, Steven Gibbs, Josephine Paolucci and the Online Distributed Proofreading Team at https://www.pgdp.net. [Illustration: _To face the Title._] EXPERIMENTS AND OBSERVATIONS ON DIFFERENT KINDS OF AIR. [Price 5s. unbound.] Quamobrem, si qua est erga Creatorem humilitas, si qua operum ejus reverentia et magnificatio, si qua charitas in homines, si erga necessitates et aerumnas humanas relevandas studium, si quis amor veritatis in naturalibus, et odium tenebrarum, et intellectus purificandi desiderium; orandi sunt homines iterum atque iterum, ut, missis philosophiis istis volaticis et preposteris, quae theses hypothesibus anterposuerunt, et experientiam captivam duxerunt, atque de operibus dei triumpharunt, summisse, et cum veneratione quadam, ad volumen creaturarum evolvendum accedant; atque in eo moram faciant, meditentur, et ab opinionibus abluti et mundi, caste et integre versentur.----In interpretatione ejus eruenda nulli operae parcant, sed strenue procedant, persistant, immoriantur. LORD BACON IN INSTAURATIONE MAGNA. EXPERIMENTS AND OBSERVATIONS ON DIFFERENT KINDS OF AIR. By JOSEPH PRIESTLEY, LL.D. F.R.S. The SECOND EDITION Corrected. Fert animus Causas tantarum expromere rerum; Immensumque aperitur opus. LUCAN LONDON: Printed for J. JOHNSON, No. 72, in St. Paul's Church-Yard. MDCCLXXV. TO THE RIGHT HONOURABLE THE EARL OF SHELBURNE, THIS TREATISE IS WITH THE GREATEST GRATITUDE AND RESPECT, INSCRIBED, BY HIS LORDSHIP's MOST OBLIGED, AND OBEDIENT HUMBLE SERVANT, J. PRIESTLEY. Transcriber's Note: Footnotes have been moved to the end of the chapter. The errata listed at the end of the book have been corrected in the text. In the text, there are places where the apothecary symbols for ounce and dram are used. These are changed to oz. and dr. in the text file. THE PREFACE. One reason for the present publication has been the favourable reception of those of my _Observations on different kinds of air_, which were published in the Philosophical Transactions for the year 1772, and the demand for them by persons who did not chuse, for the sake of those papers only, to purchase the whole volume in which they were contained. Another motive was the _additions_ to my observations on this subject, in consequence of which my papers grew too large for such a publication as the _Philosophical Transactions_. Contrary, therefore, to my intention, expressed Philosophical Transactions, vol. 64. p. 90, but with the approbation of the President, and of my friends in the society, I have determined to send them no more papers for the present on this subject, but to make a separate and immediate publication of all that I have done with respect to it.