INTRODUCTION.
Inconsequence of the discovery of the respirability and extraordinary effects of nitrous oxide, or the dephlogisticated nitrous gas of Dr. Priestley, made in April 1799, in a manner to be particularly described hereafter,[1]I was induced to carry on the following investigation concerning its composition, properties, combinations, and mode of operation on living beings.
In the course of this investigation, I have met with many difficulties; some arising from the novel and obscure nature of the subject, andothers from a want of coincidence in the observations of different experimentalists on the properties and mode of production of the gas. By extending my researches to the different substances connected with nitrous oxide; nitrous acid, nitrous gas and ammoniac; and by multiplying the comparisons of facts, I have succeeded in removing the greater number of those difficulties, and have been enabled to give a tolerably clear history of the combinations of oxygene and nitrogene.
By employing both analysis and synthesis whenever these methods were equally applicable, and comparing experiments made under different circumstances, I have endeavoured to guard against sources of error; but I cannot flatter myself that I have altogether avoided them. The physical sciences are almost wholly dependant on the minute observation and comparison of properties of things not immediately obvious to the senses; and from the difficulty of discovering every possible mode ofexamination, and from the modification of perceptions by the state of feeling, it appears nearly impossible that all the relations of a series of phænomena can be discovered by a single investigation, particularly when these relations are complicated, and many of the agents unknown. Fortunately for the active and progressive nature of the human mind, even experimental research is only a method of approximation to truth.
In the arrangement of facts, I have been guided as much as possible by obvious and simple analogies only. Hence I have seldom entered into theoretical discussions, particularly concerning light, heat, and other agents, which are known only by isolated effects.
Early experience has taught me the folly of hasty generalisation. We are ignorant of the laws of corpuscular motion; and an immense mass of minute observations concerning the more complicated chemical changes must be collected, probably before we shall be able to ascertain even whether we are capable of discovering them. Chemistry in its presentstate, is simply a partial history of phænomena, consisting of many series more or less extensive of accurately connected facts.
With the most important of these series, the arrangement of the combinations of oxygene or the antiphlogistic theory discovered by Lavoisier, the chemical details in this work are capable of being connected.
In the present state of science, it will be unnecessary to enter into discussions concerning the importance of investigations relating to the properties of physiological agents, and the changes effected in them during their operation. By means of such investigations, we arrive nearer towards that point from which we shall be able to view what is within the reach of discovery, and what must for ever remain unknown to us, in the phænomena of organic life. They are of immediate utility, by enabling us to extend our analogies so as to investigate the properties of untried substances, with greater accuracy and probability of success.
Thefirst Researchin this work chiefly relates to the production of nitrous oxide and the analysis of nitrous gas and nitrous acid. In this there is little that can be properly called mine; and if by repeating the experiments of other chemists, I have sometimes been able to make more minute observations concerning phænomena, and to draw different conclusions, it is wholly owing to the use I have made of the instruments of investigation discovered by the illustrious fathers of chemical philosophy,[2]and so successfully applied by them to the discovery of truth.
In thesecond Researchthe combinations and composition of nitrous oxide are investigated, and an account given of its decomposition by most of the combustible bodies.
Thethird Researchcontains observations on the actionof nitrous oxide upon animals, and an investigation of the changes effected in it by respiration.
In thefourth Researchthe history of the respirability and extraordinary effects of nitrous oxide is given, with details of experiments on its powers made by different individuals.
I cannot close this introduction, without acknowledging my obligations to Dr. Beddoes. In the conception of many of the following experiments, I have been aided by his conversation and advice. They were executed in an Institution which owes its existence to his benevolent and philosophic exertions.
Dowry-Square, Hotwells, Bristol.June 25th, 1800.
RESEARCH I.
concerning the analysis ofNITRIC ACIDandNITROUS GAS
and the production ofNITROUS OXIDE.
Pl. I.MERCURIAL AIRHOLDER and BREATHING MACHINE.Lowry sculpᵗ.
Pl. I.MERCURIAL AIRHOLDER and BREATHING MACHINE.
Lowry sculpᵗ.