Humphry Davy’s Early Chemical Knowledge, Theory and Experiments: An Edition of His 1798 Manuscript, “An Essay on Heat and the Combinations of Light” from The Royal Institution of Cornwall, Courtney Library, MS DVY/2

Abstract

This paper publishes, for the first time, Humphry Davy’s June 1798 “An Essay on Heat and the Combinations of Light” written in Penzance. It is the manuscript that he sent to Thomas Beddoes which secured for him the position of Superintendent of the Medical Pneumatic Institution in Bristol while aged only nineteen. It is thus a crucial document that increases our understanding about how Davy made that move from Cornwall to Bristol, without which it is highly unlikely that he would have followed the spectacular career trajectory that he did. The “Essay” provides new insights into Davy’s very early chemical reading (especially the English translations of Antoine Fourcroy’s Elémens d’histoire naturelle et de chimie), the extent to which Davy read this (and other texts) in French, the chemical apparatus he used, the experiments he made and the development and retraction of his theory of phosoxyd (later phosoxygen).

Acknowledgements

Above all I am grateful to The Royal Institution of Cornwall (RIC), Courtney Library, for permission to work on and publish this manuscript and to Angela Broome, Courtney Librarian and Archivist, for facilitating access and providing information on provenance. I am also grateful Jan Golinski for many helpful comments on an earlier version and to J.V. Field for advice on various issues raised by the text. I also thank the following for permission to study manuscripts in their possession: The Royal Institution of Great Britain (RI), Cornwall Record Office (CRO) and the Library of Birmingham (LoB).

Note on contributor

Frank A. J. L. James is Professor of the History of Science at University College London and Chair of the Society for the History of Alchemy and Chemistry. His main research concentrates on the physical sciences in the late eighteenth and nineteenth centuries and how they relate to other areas of society and culture, for example art, business, media, religion, technology and the military. He edited the Correspondence of Michael Faraday, published in six volumes between 1991 and 2012, and a number of essay collections including ‘The Common Purposes of Life’ – a set of essays on the Royal Institution. His Michael Faraday: A Very Short Introduction was published in 2010 by OUP who the following year also published his sesquicentenary edition of Faraday’s Chemical History of a Candle. His current research is on the practical work of Humphry Davy, including his work on nitrous oxide, agricultural chemistry, mineralogy, the miners’ safety lamp, analysis of ancient Roman pigments and his attempts to unroll chemically the papyri excavated from Herculaneum. He has been President of the British Society for the History of Science, the Newcomen Society for the History of Engineering and Technology and the History of Science Section of the British Science Association. He was elected a Member of the Academia Europaea in 2012 and is a Membre Effectif of the Académie internationale d’histoire des sciences. Address: Department of Science and Technology Studies, University College London, Gower Street, London WC1E 6BT, UK. Email: [email protected].

Notes

1 For example, David Knight, Humphry Davy: Science and Power (Oxford: Blackwell/Cambridge: Cambridge University Press, 1992/1996) and June Z. Fullmer, Young Humphry Davy: The Making of an Experimental Chemist (Philadelphia, PA: American Philosophical Society, 2000).

2 James Watt Jr to John Craig, 24 September 1831, Royal Institution (hereafter RI) MS HD/26/D/67.

3 Frank A. J. L. James, ‘the first example  … of an extensive scheme of pure scientific medical investigation’: Thomas Beddoes and the Medical Pneumatic Institution in Bristol, 1794 to 1799 (London: Royal Society of Chemistry Historical Group Occasional Papers No. 8, 2016), 34.

4 Humphry Davy, “An Essay on Heat and the Combinations of Light,” The Royal Institution of Cornwall, Courtney Library (hereafter RIC) MS DVY/2. This will be cited as Davy, “Essay” MS; pagination will refer to the MS.

5 Jan Golinski, The Experimental Self: Humphry Davy and the Making of a Man of Science (Chicago, IL: University of Chicago Press, 2016), 20–21.

6 Humphry Davy, “An Essay on Heat, Light, and the Combinations of Light,” in Contributions to Physical and Medical Knowledge, Principally from the West of England, ed. Thomas Beddoes (London: Longman, printed Bristol, by Biggs and Cottle, 1799), 5–147 and “An Essay On the Generation of Phosoxygen (Oxygen Gas) and on the Causes of the Colors of Organic Beings,” in Contributions to Physical and Medical Knowledge, 151–205. These will be cited respectively as Davy, “Heat, Light, and the Combinations of Light” and Davy, “Generation of Phosoxygen.”

7 Knight, Humphry Davy; Fullmer, Young Humphry Davy. Indeed, I only located the manuscript by pursuing the clue given in the reference cited in note 103. However, since then Angela Broome, “The Courtney Library, 1818–2018,” Journal of the Royal Institution of Cornwall (2018): 151–73 on 153 has referred to it in a special issue of the Journal marking the bicentenary of the Royal Institution of Cornwall.

8 Fullmer, Young Humphry Davy sought (58, 68–69) to reconstruct some of Davy’s pre-Bristol researches from a reading of his 1799 publications.

9 RI MS HD/20/B, 186.

10 RI MS HD/20/B, 190.

11 For the history of this text and of the materials from which it was constructed see Frank A. J. L. James, “Constructing Humphry Davy’s Biographical Image,” Ambix 66 (2019): 214–38.

12 John Davy, Memoirs of the Life of Sir Humphry Davy, Bart., 2 vols. (London: Longman, 1836), Vol. 1, 42; Knight, Humphry Davy, 20; Fullmer, Young Humphry Davy, 46–61.

13 Davy, Memoirs, Vol. 1, 42.

14 RI MS HD/20/B, 190. Davy, Memoirs, Vol. 1, 42.

15 I am grateful to a referee for this valuable suggestion.

16 William Nicholson, A Dictionary of Chemistry, 2 vols. (London: Robinson, 1795), Vol. 2, 641.

17 William Nicholson, The First Principles of Chemistry, 3rd ed. (London: Robinson, 1796), 91.

18 Davy, “Essay” MS, 31. Davy omitted mentioning Kirwan entirely in the published version of his “Essay.”

19 Antoine François Fourcroy, Elements of Natural History and of Chemistry, trans. William Nicholson, 4 vols. (London: Robinson, 1788), Vol. 1, vii.

20 Davy, “Essay” MS, 29. Fourcroy, Elements of Natural History, Vol. 1, xi–xvi. For a discussion of Nicholson’s role in the controversy see David Philip Miller, Discovering Water: James Watt, Henry Cavendish and the Nineteenth-Century ‘Water Controversy’ (Aldershot: Ashgate, 2004), 62–63. Davy’s reference to Cavendish was omitted in Davy, “Heat, Light, and the Combinations of Light,” 62 – possibly due to his not supporting Beddoes’s fundraising efforts, James, ‘the first example  … ’, 21–22.

21 Davy, “Essay” MS, 49–50; Antoine François Fourcroy, Elements of Chemistry and Natural History to Which Is Prefixed the Philosophy of Chemistry, trans. Robert Heron, 4 vols. (London: Murray and Highly, 1796), Vol. 3, 147–48.

22 Davy, Memoirs, Vol. 1, 21; John Ayrton Paris, The Life of Sir Humphry Davy, Bart., 2 vols. (London: Colburn and Bentley, 1831), Vol. 1, 16.

23 Paris, Life, Vol. 1, 24 and a recollection by Davy’s sister, Katherine Davy, c.1830s, RI MS HD/26/D/79, 2r. Fullmer, Young Humphry Davy, 22 quoted the poem from a play performed in Paris in 1854, La Lampe de Davy ou L’Armour et le Travail in Christien Ostrowski, Théatre Complet, 3rd ed., 2 vols. (Paris: Fermin Didot, 1862), Vol. 1, 277–303, 301. Assuming the poem was by Davy, quite how Ostrowski came across it is not known.

24 Davy, “Essay” MS, 3.

25 Davy, “Essay” MS, 29.

26 Davy, “Essay” MS, 21–22.

27 Fourcroy, Elements of Chemistry, Vol. 1, 98. However, in the printed text Davy, “Heat, Light, and the Combinations of Light,” 51 he referenced and quoted the passage in French from Antoine François Fourcroy, Elémens d’histoire naturelle et de chimie, 3rd ed., 4 vols. (Paris: Cuchet, 1789), Vol. 1, 126–27.

28 Antoine Lavoisier, Traité élémentaire de chimie, 2 vols. (Paris: Cuchet, 1789), Vol. 1, 192. For further discussion see Hasok Chang, Is Water H₂O? Evidence, Realism and Pluralism (Dordrecht: Springer, 2012), especially chapter 1.

29 Davy, Memoirs, Vol. 1, 43–44.

30 James, “Constructing Humphry Davy’s Biographical Image,” 223.

31 Davy, Memoirs, Vol. 1, 43; Paris, Life, Vol. 1, 41.

32 Davy, “Essay” MS, 23 and 55 respectively. For the prevalence of the chemical use of domestic items see Simon Werrett, Thrifty Science: Making the Most of Materials in the History of Experiment (Chicago, IL: Chicago University Press, 2019), especially chapters 2 and 5.

33 Davies Giddy to Thomasina Dennis, 17 November 1798, Cornwall Record Office (hereafter CRO) DG/87/1/20.

34 Davy, Memoirs, Vol. 1, 48.

35 Katherine Davy, Recollection, 4 January 1831, RI MS HD/26/D/79, 3r–v.

36 Gregory Watt to James Watt Sr, 22 March 1798, Library of Birmingham (hereafter LoB) MS 3219/7/49/12, written from Truro.

37 Davies Giddy to Gregory Watt, 18 July 1798, LoB MS 3219/7/5/54.

38 Paris, Life, Vol. 1, 47. Probably taken from a recollection by Gilbert.

39 Davies Giddy to Gregory Watt, 20 January 1798, LoB MS 3219/7/5/53.

40 Davy, Memoirs, Vol. 1, 51.

41 Referred to in Davies Giddy to Gregory Watt, 20 January 1798, LoB MS 3219/7/5/53.

42 Gregory Watt to James Watt Sr, 19 January 1798, LoB MS 3147/3/76/03.

43 Davy, “Essay” MS, 20 only cited the first volume.

44 Davy, “Essay” MS, 21 (note). S. Miller, An Inquiry into the Cause of Motion; or, a General Theory of Physics, Grounded upon the Primary Qualities of Matter (London: The Author, 1781), 24–25.

45 Augustus De Morgan, A Budget of Paradoxes (London: Longman, 1872), 100.

46 Davy, “Heat, Light, and the Combinations of Light,” 51 with attribution. Isaac Newton, Opticks: or, A Treatise of the Reflections, Refractions, Inflections and Colours of Light, 2nd ed. (London: Innys, 1718), 314–18.

47 Davy, “Essay” MS, 27. Newton, Opticks, 160–61.

48 Fourcroy, Elements of Natural History, Vol. 1, 166. There was no reference to this in the 1796 translation.

49 On this see W. H. Pascoe, CCC. The History of the Cornish Copper Company (Hayle: Haylebooks, 1981).

50 Paris, Life, Vol. 1, 47. Probably also taken from a recollection that Gilbert gave Paris.

51 Davy, “Essay” MS, 3.

52 Davies Giddy to Gregory Watt, 18 July 1798, LoB MS 3219/7/5/54.

53 Davy, “Essay” MS, 46 (note).

54 Rumford, “An Inquiry concerning the Source of the Heat which is excited by Friction,” Philosophical Transactions 88 (1798): 80–102.

55 Thomas Beddoes to Davies Giddy, 14 April 1798, CRO DG/42/2.

56 Paris, Life, Vol. 1, 52.

57 Thomas Beddoes to William Reynolds, nd but late April 1798 in John Stock, Memoirs of T. Beddoes, M.D., with an Analytical Account of His Writings (London: John Murray, 1811), 155.

58 Davy, “Generation of Phosoxygen,” 199.

59 Davy, “Essay” MS, 1.

60 Davy, “Essay” MS, 1. Davy might have come across the translations of Girtanner’s work in Thomas Beddoes, Observations on the Nature and Cure of Calculus, Sea Scurvy, Consumption, Catarrh, and Fever: Together with Conjectures upon Several Other Subjects of Physiology and Pathology (London: Murray, 1793), 171–268.

61 Davy, “Heat, Light, and the Combinations of Light,” 7.

62 Davy, “Heat, Light, and the Combinations of Light,” 9 where he quoted Lavoisier, Traité, Vol. 1, 6.

63 See his notebook, RI MS HD/21/A.

64 Davy, “Essay” MS, 4–6; Davy, “Heat, Light, and the Combinations of Light,” 16–20. Night temperatures for most of March 1798 fell below freezing point in London see “Meteorological Journal,” Philosophical Transactions 89 (1799): 6–7.

65 Davies Gilbert, “[Presidential] Address [to the Royal Society of London],” Philosophical Magazine 7 (1830): 33–46 on 38.

66 Davy, “Essay” MS, 4.

67 Davy, “Essay” MS, 3. Fourcroy, Elements of Chemistry, Vol. 2, 272.

68 Davy, “Essay” MS, 18 where he also gave the derivation of the term from the Greek, illustrating what he had learnt from his year attending Truro Grammar School in 1793.

69 Davy, “Essay” MS, notes to 2, 21, 31.

70 Fourcroy, Elements of Natural History, Vol. 1, 134.

71 Davy, “Essay” MS, 60–63.

72 [Thomas Beddoes], Alexander’s Expedition Down the Hydaspes & the Indus to the Indian Ocean (London, Murray, 1792), 80.

73 See Thomas Moore’s diary entry for 24 March 1824 in John Russell, ed., Memoirs, Journal, and Correspondence of Thomas Moore, 8 vols. (London: Longman, 1853–1856), Vol. 4, 172.

74 Davy, “Essay” MS, 45. Jan Ingen-Housz, “On the Degree of Salubrity of the Common Air at Sea, Compared with that of the Sea-Shore, and that of Places far Removed from the Sea,” Philosophical Transactions 70 (1780): 354–77.

75 Davy, “Essay” MS, note to 57.

76 Davy, “Essay” MS, 64. For a brief discussion see Frank A. J. L. James and Sharon Ruston, “New Studies on Humphry Davy: Introduction,” Ambix 66 (2019): 95–102 on 99.

77 Davy, “Essay” MS, 64.

78 This date of its receipt was given in Thomas Beddoes, “Specimen of an Arrangement of Bodies according to their Principles” in Beddoes, ed., Contributions, 207–30 on 212.

79 Thomas Beddoes to William Reynolds, nd but late April 1798 in Stock, Memoirs of T. Beddoes, 155.

80 Paris, Life, Vol. 1, 52, another story that that Paris probably received from Gilbert. Gregory Watt to Boulton & Watt, 12 June 1798, LoB MS 3147/3/76/11 written from Truro, noted he was about to depart for Birmingham. That Watt called on Beddoes on his way to the Midlands is evident from Thomas Beddoes to James Watt Sr, 15 July 1798, LoB MS 3219/4/29/32 discussing Davy’s appointment to the Medical Pneumatic Institution. The chronology of these events given in Fullmer, Young Humphry Davy, 88 is incorrect.

81 Giddy, Diary, 31 May 1798, CRO DG/16 (no pagination).

82 Which Davy noted in RI MS HD/20/A, 201.

83 Davy, “Essay” MS, 42, 47, 48 (note) and 51.

84 Davy, “Essay” MS, 62, 57 and 61 respectively.

85 Thomas Beddoes to James Watt Sr, 15 July 1798, LoB MS 3219/4/29/32.

86 Thomas Beddoes to Davies Giddy, 4 July 1798, Paris, Life, Vol. 1, 53.

87 Humphry Davy to Henry Penneck, 26 January 1799, in The Collected Letters of Sir Humphry Davy, ed. Tim Fulford and Sharon Ruston, advisory ed. Jan Golinski, Frank A. J. L. James and David Knight, 4 vols. (Oxford: Oxford University Press, 2020), Vol. 1, letter 9 (hereafter cited as Davy, Collected Letters followed by volume and letter number).

88 Davy, “Heat, Light, and the Combinations of Light,” 6, 13, 109 (Black), 64 (Hutton), 55–56 (Wedgwood).

89 Davy, “Heat, Light, and the Combinations of Light,” 111–12.

90 Thomas Beddoes to Davies Giddy, 5 March 1799, CRO MS DG/42/12.

91 COPAC notes the existence of just five copies throughout the world. Accessed 27 May 2019.

92 Humphry Davy to Henry Penneck, 26 January 1799, Davy, Collected Letters, Vol. 1, letter 9; Humphry Davy to Grace Davy, 18 January 1799, Davy, Collected Letters, Vol. 1, letter 7.

93 Humphry Davy to Henry Penneck, 26 January 1799, Davy, Collected Letters, Vol. 1, letter 9.

94 Humphry Davy to Davies Giddy, 22 February 1799, Davy, Collected Letters, Vol. 1, letter 10.

95 Davies Giddy to Thomasina Dennis, 28 February 1799, CRO MS DG/87/1/25.

96 Humphry Davy to Davies Giddy, 18 April 1799 Davy, Collected Letters, Vol. 1, letter 14.

97 Respectively Humphry Davy, “Letter  … Introductory to the Experiments Contained in the Subsequent Article, and on Other Subjects Relative to the Progress of Science,” A Journal of Natural Philosophy, Chemistry and the Arts 3 (1799): 55–6 and “Extract of a Letter,” A Journal of Natural Philosophy, Chemistry, and the Arts 3 (1799): 93.

98 Humphry Davy, “On the Nitrous Oxide, or Gaseous Oxide of Azote, on Certain Facts Relating to Heat and Light, and on the Discovery of the Decomposition of the Carbonate and Sulphate of Ammoniac,” A Journal of Natural Philosophy, Chemistry, and the Arts 3 (1799): 515–18 on 517.

99 RI MS HD/20/B, 188. Probably written in August 1799.

100 Davy, Memoirs, Vol. 1, 80.

101 Davy, Memoirs, Vol. 1, 80–84.

102 RIC MS DVY/1 (Davy’s half is in RI MS HD/5/3); Edmonds’s possession of the indenture is referred to in Paris, Life, Vol. 1, 14.

103 George Clement Boase and William Prideaux Courtney, Bibliotheca Cornubiensis: A Catalogue of the Writings, Both Manuscript and Printed, of Cornishmen, and of Works Relating to the County of Cornwall With Biographical Memoranda and Copious Literary References, 3 vols. (London: Longman, 1874–1882), Vol. 1, 108.

104 Edmonds’s will in the Principal Registry of the High Court.

105 The earliest record that the “Essay” was in the possession of the Royal Institution of Cornwall is in 1929 when it was lent to the Royal Geological Society of Cornwall for their commemoration of the centenary of Davy’s death, but it is highly likely that it had been in the Royal Institution of Cornwall for some time before then. Private communication from Angela Broome.

106 Except by Macquer, who I believe substituted it for Phlogiston.

107 Lavoisier Traité elementaire. Tom premier. p 6 -

108 This confutes directly the great Euler’s opinion.

109 Heat in common Language signifies that sensation which accompanies an increase of corpuscular motion in any part of our system. It should not therefore be used for the corpuscular motion or cause of that sensation. The Caloric of the French Nomenclators is equally exceptionable. For having been generally used to signify the imaginary fluid or matter of Heat it is now associated with & generally suggests that idea & would thus if used to express the corpuscular motion be a source of error. - - Words expressing compound ideas should when optionally form’d express as near as possible the component parts of the idea, when these component parts are known. - - - 8 The word corpuscular Motion is liable to no exception I shall therefore use it to express the cause of our sensations of Heat & as the cause of those changes in bodies which are consequent on an increase of temperature. - - -

110 Read that bodies having their particles affected with greater or less quantities of corpuscular motion.

111 The sensation of cold arises from a communication of a portion of our corpuscular motion, to some body or bodies of a lower temperature[.] It is probable that cold & & [sic] the consequent shiverings may be felt from peculiar changes of the corpuscular motion taking place in the system.

112 are converted into - - -

113 Read subtracted  The reason why they are disposed to take the form of Gas whe[n] exposed & not when confined in closed vessels is from the resistance given to their elastic force by the vessel confining them

114 Read deprives of

115 Read The impression of an external force upon bodies communicating motion is one cause of an increase of temperature in bodies

116 Read Corpuscular motion

117 [Note indicated, but none given]

118 From Φϖς and Οζνς

119 This Theory of the luminous appearance of bodies may be compared with Macquers & Newtons. Fourcroy says Tom 1, p 96. The ignition of incombustible bodies has been very ingeniously explained by Macquer. In his opinion it depends on the strength of vibrations communicated to the particles of these bodies by the impulse of heat. Those vibrations disposing the particles in such a manner, that their facets acting like so many little mirrors 22 reflect upon our eyes the rays of Light, which exist in the air by night as well as by day. For we are involved in darkness during the night for no other reason but because these are not then so directed as to fall upon our organs of sight /// A most curious explanation. How much more philosophical is the common opinion of Mankind who ignorant & unphilosophic suppose that the presence of the Sun is the cause of Light & his absence of darkness ///- - Newtons opinion is more ingenious. He supposes that when the corpuscular motion of bodies is raised to a certain degree The agitation throws off some subtle particles or effluvia which excite the idea of light.-- that when the particles of bodies are violently agitated - They not only throw off lucid particles but also shine themselves & then when the bodies are solid the red 23 Heat is produced when they are in a fuming state the Flame. --- The first Exp^t confutes the last opinion that light is the effect of Heat & it will appear in the course of these exp^ts & observations That fixed & fluid light are never present but when Oxygen Gas or phosoxyd is decomposed, or light condensed by solid or fluid bodies. - - -

120 ie vibrate

121 All the phænomena of the decomposition of the rays by the prism their refraction, their similarity &c &c may on this supposition be easily accounted for. - -

122 [No indication of location] tinged with yellow or green. – Dr Hall[e]y in the diving bell exposing his hand to the solar rays it became tinged red.

123 Phosoxyd [here and in the following notes on this page, Davy refers using the same symbol to the note five more times]

124 Phosoxyd

125 Phosoxyd

126 Phosoxyd

127 Phosoxyd

128 pure charcoal freed from Hydrogen - - -

129 Phosoxyd

130 The composition of water, that most important chemical truth was discovered by Cavendish & Lavoisier at nearly the same <time>. The latter has given the most convincing synthetical & analytical proofs, Traite elementaire Tom. premier

131 With a similar apparatus two Flints were made to strike together in vacuo, but no light was produced in carbonic acid Gas; but no light 31 was produced [sic]. Small particles of Flint were separated unaltered. When the Collison was made in Oxygen Gas or atmospheric air Light was produced, small pieces were separated from the Flint which examined by the microscope appeared whiter than before. Now it is evident since Oxygen Gas is decomposed, that the Oxygen must either combine with the Flint or some metallic substance in the Flint whilst the light is liberated. This Exp^t may lead to some discovery of the nature of Siliceous earth. I am about to make exp^ts on it with a better apparatus. - - -

132 Macquer (as I believe) supposed light to be the Phlogiston & Kirwan Hydrogen

133 It might be more accurately expressed. Combustion then is the decomposition of Phosoxyd or Oxygen Gas by the simple elective attraction of the oxidable base for oxygen &c - - -

134 Add here. Exp^ts on the decompositions of combinations of Oxygen by the simple elective attraction of light for oxygen.

135 The marine Cryptogamia or vegetables, placed in contact with water & dep^d of light produce no Gas & effect no alteration in the water as long as they retain life.- - -

136 I must here observe that these exp^ts on the decomposition of water afford strong proofs of its composition, a fact which is still contested by D^r Priestl[e]y & some other Chemists.- Water holds in solution a considerable portion of Atmospheric air which even boiling will not entirely free it of. The Azote produced in these exp^ts must arise from the Atmospheric air & -

137 I must here observe that those facts afford additional proofs of the truth of the Theory of Light. In that theory it was stated that dark colors were occasioned by a diminution of the velocity of the vibrations of the particles of Light, by the communication of portions of their motions to reflecting bodies. The particles of light must therefore remain longer in contact with those bodies & must thus more effectually act upon the oxygen of the water whilst the Hydrogen is attracted by the Cryptogamia. We as yet know but very little of the corpuscular action. Chemical not mathematical principles are the only ones by which we can hope to discover it.

138 [Davy did not indicate where this note should go]: M [blank in MS] Oxygen combined with still greater portion of light here

139 I have heretofore possessed no ballance sufficiently accurate to determine the weight of Light in a fixed state – By discovering the quantity of Light liberated in combustion & by comparing the weight with the magnitude & duration of the flame we may be enabled to ascertain the specific gravity of light. These exp^ts. I intend to make as soon as I am possessed of a ballance & the necessary apparatus sufficiently accurate - - - -

140 Count Rumford supposes (in a paper published in the last volume of the philosophical transactions) that the explosive force of Gunpowder is owing to the aqueous Gas generated in the process which must chiefly arise from the water of chystallisation of the nitrate of potash. It will be sufficient to confute this opinion to observe that Gunpowder made with nitrate of Soda is not near so strong as that made with nitrate of Potash altho’ it contains three times as much water of chystallisation. That the formation of Gases is the great cause of this explosion is evident from the phænomenon of the air gun.- - -

141 Since such is the composition of the nitrous oxyds & acids it is evident that the names given to them by the French nomenclators are improper. If Azote be admitted as the name of the base. The combination of Azote should be distinguished by names expressive of the substances forming the compound – As the nitrous Oxyds & Acids are compounds of 49 Light, Oxygen & Azote. They should be distinguished by the following names Gaseous Oxyd of Azote, the Dephlogisicated nitrous Gas of Priestl[e]y should be called a Azotous Phosoxyd. The nitrous oxyd Gas – the nitrous Gas of Lavoisier should be called Azotic Phosoxyd. The nitrous acid should be called Azotous Phosacid – The Nitric acid Azotic Phosacid. The terminations ous & ic & the terms Oxyd & Acid would easily point out the different proportions of Oxygen Light & Azote. But I shall treat more fully of this in my Essay on the combinations of Azote.- - -

142 Since Oxygenated Muriatic Acid is thus compounded it is evident that its present name is not expressive of its composition. The composition of the muriatic acid is unknown. Analogy induces us to suppose that it is a compound of some unknown base with Oxygen. The Oxygen^d: Muriatic Acid is a compound of Muriatic Acid with Light & Oxygen it shou[l]d be therefore called muriatic phosacid & its compounds phos’muriates.- From the mode of its generation it may be likewise induced that it is a compound of Muriatic acid, Light & Oxygen.---Muriphosa[c]id.

143 It is evident that the common name of Oxyd as applied to all the combinations of metallic substances with Oxygen & Light is very improper & if preserved in the nomenclature will be a source of error. Those bodies simply combined with Oxygen should be called Oxyds. Those bodies combined with Light & Oxygen should be called Phosoxyds as Phosoxyd of Mercury to express the Red Oxyd of Mercury. - - - - -

144 The beautiful red of the arterial blood would alone analogically prove the existence of light in it.

145 There are as well analytical proofs which I shall give in another place. In Land Animals the light combined with the system forms with Oxygen & Azote, Nitric Acid – in fish &&c it is liberated from hence fish when decomposing are luminous in the dark & list more of this is my essay on the Combinations of Azote.- - -

146 There are a great number of Physiological facts which prove this, Animals die in a few minutes deprived of Oxygen Gas. Stricture upon the carotid arteries deprive animals of Sensation & voluntary power &cc.

147 It appears from astronomical observations, that all the planets have atmospheres.- Since Oxygen & Light are essential to the organic existence of all the beings on our globe & Since Light is supplied to the planets in the same manner as to our earth Analogy would induce us to believe (& we can here expect no other proofs) & that those atmospheres are similar in their composition with regard to oxygen Gas. The Lunar volcanoes will almost demonstrate that she has such as atmosphere. The solar atmosphere or the [word illegible] luminosa discovered by Cassini is of an amasing extent it is indeed supposed to extend to the plane of the earths orbit. May not this atmosphere be a compound of Oxygen with a very large proportion of Light. May not the sun be an immense Oxygen attractor. Then will the solar light arise from the decomposition of the Oxygen Gas in contact with the sun of which the oxygen combines with some bodies in the sun & the Light is liberated & this atmosphere continually wasted by decomposition may be partly supplied by the sun & partly from the planetary atmospheres which may as was before mentioned become so extremely rare & extend to so great a distance from there as to be attracted by the sun & to form a part of his orbit.

148 [No note]

149 In fact plants will not grow without Light; plants when arrived at Maturity will continue to vegetate even when deprived of Light & will as is just going to be proved suffer great changes from the privation - - - -

150 58 Or that peculiar disposition to receive a portion of the corpuscular motion of Light or to diminish the velocity of the vibrations appears to depend on the quantity of light or of Phosoxyd combined with them.

151 When the color of animals become hereditary, it requires a considerable time to effect the changes of color. Europeans are not made perfect negroes tho’ much exposed to the stimulus of Light in the affrican countries for many generations and Negroes are not blanched except in a great length of time by the abstraction of Light - Thus the generating Mind which influences all the chemical changes which take place 61 in the animal oeconomy exerts its energies[.]

152 By the application of Oxygenated Muriatic acid or of diluted Sulphuric acid in the dark. These do not act on the skin in the light for Light attracts Oxygen stronger than the skin - - - -

153 It shou[l]d be expressed than those of the countries under the equator - -

154 This doctrine of color will confirm D^r Beddoes’s ingenious Theory of Scurvy & consumption. The philanthropic exp^t made by the D^r on himself deserves the eternal approbation of Mankind – vide his letter to D^r Darwin -- That exp^t confirms this theory. The pale & shrunk experience of the skin in Typhus fever – the febris irritativa of D^r Darwin proves the deficiency of light which is most certainly one of the principles of the seminal fluid in the system. - - - - - - - - -

155 [No note].

156 No physiological fact is better established.

157 & of animating power