[Episteme is sorry that, due to the poor quality of the printed copies taken from the microfilm of the original book in British Museum, London, and the consequent difficulties in the scanning operation, it has been possible to present to the readers in this number 3 only but the Preface and the Table of Contents of the remarkable work by John Cook, in place of the more exhaustive selection that was originally planned].

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Clavis Naturae: or, the Mystery of Philosophy Unvail'd

In a DISCOURSE shewing The prime and efficient Physical Cause of all the Phaenomena of Nature, and singular Motions in the whole Universe, by which the Knowledge of Natural Philosophy is render'd obvious and easy,

and the Sum of the Whole is reduc'd to one single Point

(John Cook)


Felix qui potuit Rerum cognoscere Causas.

...ruit arduus Ether.

Virg. Georg. Lib. I & II





ALTHO' it is not always necessary to write Prefaces to such small Discourses, yet the Oddness of the Subject treated of in This, gives me a special Demand for so doing: both to prevent interrupting the Thread of my following Treatise, by mentioning there what becomes this Place much better; and likewise to describe, in one View, the various Tempers and Dispositions of all those Readers in whose Hands this Book may chance to happen: and, Lastly, to say somewhat in respect to myself, by way of my Design in writing this; and Excuse for any Mistake or Error that may perhaps be found therein.

AS to the various Tempers of Men in relation to reading Authors, the chief of them may well be reduced to these following: The Morose; the Insipid; the Bantering; the Judicious and Candid.

NOW the first Set of these Creatures can seldom read any Book without greatly condemning it; not so much thaf it realIy deserves it, but because they cannot like it : For to them every Escape is a grand Fault, and a Mistake tho' ever so small is unpardonable; in short, they like Nothing that they have not a Hand in themselves, and yet it is seldom seen that they do any thing at all; or, if it so happen that they do, it is generally as ill performed by them, as by those whom they had the Ill-Nature to condemn. The Whole of the Matter then is; Nothing can please these Set of Men; and to be up with them, I think there should be as little Care taken, on the other hand, to do it; which is my own Case intirely: I will do my Best, and if they don't like it, let them do better if they can; if not, let them even possess their Ill-Nature to themselves as a due Reward to their Uncharitableness, and be therefore esteemed below the Regard of all civil, discreet and candid Men.

THE next Set of Readers are the Insipid; who read Books they know not why, and run over them without either Sense, Knowledge, or Design. These indeed, as they do no manner of God, they likewise do no great Harm; only are so many Blanks among human Figures, and do thereby betray either their Education, or Intellectuals, and represent so many moving Statues without either Soul, Sense, or Taste in them.

BUT worse than either of these, are the Bantering Readers, who can toss up their Nose a every thing they do not understand, and with no small Assurance reckon themselves competent Judges of all that can be wrote or said, and even without ever so much as giving themselves Leisure or Pains to read what they so condemn. Truly these are those very Fools, of which Solomon says, That tho' they be even brayed in a Mortar, yet they will not be made wise. These are Fools, indeed! who scoff at Knowledge, and despise Wisdom, and there is greater Hopes of any seeming Impossibility, than there is of reclaiming them. These are the Gentlemen who neglect Knowledge, and hate Instruction; who say, Cui Bono? What are we the better for these Things? As if, forsooth, a Man who worships and adores his Maker with knowledge, had not the Advantage of him who knows nothing but that he ought to do so. They forget the sublime Thoughts of David, and the Sacred Philosophers, who admired the Sun, Moon, and Stars, the Works of God's Hands; and have told us, They are many and wonderful, soughr out by all those who take Delight therein. But these Gentlemen's Diversions lie in a much meaner Plan, about impertinent Trifles and Fopperies, far below Human Nature, and the Dignity of a rational Soul to busy itself about: Besides, without entering into a long Detail of Arguments with these indolent, insensible Creatures, the Matter is answer'd at once, and the grand Question, Cui Bono? is finally decided: For what is the Intention of all our Actions but to improve Knowledge? And what are the Advantages of Knowledge, but to provide all Necessaries and Comforts to our Bodies; such as Food, and Rayment, (and which is the least Part;) and to improve the Light of the Mind, the sweet Contemplation of God and his Works? Now because every Article of Knowledge hath no direct Tendency to get a Penny, must it be therefore laid aside as useless? What a strange and stupid Fancy would this be! Truly, beneath my saying more of it, and very unworthy a rational Being to think so. But these merry Gentlemen take a Delight to betray their slender Brains in ridiculing the innocent Diversions of Philosophers, and vainly imagine that none in the World are wiser than themselves. Yet these shall never deter me from my Purpose, but let them laugh on, and shew themselves like Nature's Asses, by braying at what they have not Heads capable to understand; and as Truth and Knowledge are not any Ways indebted to them, neither can they in the least destroy or damnify it, but like indifferent Creatures, subsist only to shew themselves Nature's Monkeies to mimick, and endeavour all the Mischief to Natural Knowledge that they can. But as it is with them, so it is with these; they have truly got Superiors, who will take sufficient Care never to let them have their Wills.

LASTLY, the judicious and candid Reader is he who reads with Judgement, censures kindly, and excuses Human Frailties in Writings; knowing that none can wirte perfect, but that every Man has his Defects in one Point or other: This is the Person, whom I desire should read my Book, and from him ask Parson for what is amiss. As for all other sort of Men, I shall value their Judgement as little as they shall value my Doctrine, but shall be ready and willing to answer them, whenever they shall think fit, publickly, to gainsay my Theory.

FINALLY, As to myself, all my Design in writing this Treatise was to divert my own Mind, and all those who may take Delight in the same; to endeavour some farther Advancement in the Knowledge of Nature, and sweetly to contemplate the wonderful Works of our Maker. If I have performed it tolerable (for well I never shall pretend to,) I shall be glad; and if not, shall be well plesed to see it done better by a more able Pen. We have Instances of *Great Men, who have only amused themselves and the World with curious Fancies: If mine, at last, does not only amount to that, I shall think my small Pains well bestowed; and if, after all, I can gain but a single well pleased Smile from any of the Learned, by what I have here done, my Reward will be sufficient.

* M. Fontenelle's Plurality of Worlds. Huygen's Inhabitants of the Worlds in the Planets.

AS to the Correctness of the Style, I must needs make this Apology for it: That it is the Matter treated of, and not the Manner, that is the chief Intention I am at. Therefore I endeavour not at so much exciting the Passions, as barely relating the Truth, and laying down the Circumstances of my Theory with a free and natural Plainness. Nor would I have thought by any, that it was a vain or foolish Itch or Curiosity of being an Author, that was the Motive of my Publishing this; but would rather have them believe me, it was the endeavour at a farther Advancement of Physical Knowledge, and render the long and tedious Labyrinth of Philosophy, acquired from reading obscure, prolix, and voluminus Authors, short and easy, and to explain farther the Cause of the Causes, whereby even those excellent Pieces of the Famous Doctors *Mead and = Friend, may gain farther Improvement, in having the very Ultimate Cause of their Effects discovered and accounted for.

* De Imperio Solis & Lunae in Corpore Humano. = Pralectiones Chymicae.

THEREFORE, I say, as the Subject was something new, and but little touch'd upon by Authors, I proposed this Essay to myself, thinking thereby to render this Doctrine of Aether more common and intelligible: And as it is so, I could gain but very small Assistance from the Works of greater Men; since most of them take but little or no Notice of it, and those who do, do but just mention it as a fine Fluid, they know not what. Therefore whatever may be the Success of this Undertakinh, I hope my Intention will be accounted laudable, by the Curious; and that they will ever encourage such Essays, 'till some better are performed in their Stead. And as Prefaces are generally reckoned tedious, when they extend a moderate Bounds, I shall add no more to detain the Reader, but conclude with due Respects to Learning and all learned Men.

GO then, little Book, into this ungrateful World, and take your Lot amongst Men of many Tempers; and if chance be, you meet with bad Treatment, it's no more than what your Betters have been so served, and rnuch worse, before you.



Dente Theonino quid carpis, Zoile? Nostra

Si tibi displaceant, fac meliora, precor.


Leigh in Essex,

October 30th, 1732.

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. I. Of Matter and Motion.

1. Matter and Motion the two Grand Subjects of all Physical Studies.

2. A Phaenomenon is any Report of any of our Senses concerning external Objects.

3. Natural Philosophy teaches us the common and ordinary Laws of Nature, whereby such and such Phaenomena are produced; and when any Phaenomenon is agreeable to those Laws, it is then called a Natural Phaenomenon; and otherwise it is called a Supernatural one, or a Miracle.

4. Of Matter and its Substance, and how far our Knowledge can possibly reach in that Affair.

5. Of its three General Properties, Extension, Impenetrability, and Divisibility, which are all inseparable Qualities of Matter.

6. First, Of Magnitude, and wherein that consists.

7. Secondly, Of Solidity and the Nature of it.

8. Thirdly, Of its Subtilty, and the great Extent of the same.

9. The seeming Mystery of the infinite Divisibility of Matter considered, and the Pretended Absurdity objected against it obviated.

10. Of the two other Properties of Matter, which tho' not essential to it, yet are common and necessary, viz. Rest and Motion.

11, 12, 13, 14. Of Space or Vacuum, and its Reality proved, and the Necessity of it shown.

15, 16. Of the other Grand Principle of Nature, viz. Motion, and what it is.

17. Of the Singularity of Motion as well of Matter.

18. Of its Variety in relation to the Subject acted upon: The first called the Attraction of Cohaesion: The second Attraction of Gravitation; tho' very improperly so termed if we respect the Cause, yet tolerable if we only regard the Effect.

19. Of the constant Regularity of the Laws belonging to these said Motions.

20, 21. The Law of Attraction of Cohaesion particularly examined, and the Nature of it explained.

22, 23. The same further consider'd.

24. Of the different Forces of Cohaesion in different Bodies, and their Cause.

25, 26. Of the different Consistencies of Fluid Bodies, with the Physical Reason of the same.

27, 28. Of the Law of Repulsion, and the many Effects arising from it.

29. Of the nice and wonderful Provision of Nature in the Cohaesion of Water, so wisely suited for its particolar Usefulness.

30. Of the other singular Division of Motion; namely, that of Gravitation, and how it affects all Planets.

31. Of its being the Cause of Weight, and Falling of Bodies, of the Tides, etc.

32. Of its other Properties in relation to our own Earth further consider'd, with a new and more natural Account of the Physical Cause of the Flood of Noah than any yet extant.

33. Of the Equality and Unequality of the force og Gravity in different Parts of the Earth, and its Cause.

34. Of its equally affecting all Bodies alike upon our Globe.

35. Absolute Levity and Unentity in Nature.

36. Of the Increase and Decrease of Gravity the nearer or further from the Body of the Earth.

37. Of the several Laws of Motion.

38, 39. The first Law fully considered for our Purpose.

40. Of the second Law of Motion, and its Necessity according to our Theory.

41, 42. Of the third and last Law of Motion, and its Effects upon Material Subjects.

43, 44. Of the Physical Cause of all these Motions.

45. Aether is all and the only Natural Cause of the same.

46. Aether, what it is explained.

47. An objection against the same answered.

48. The same further consider'd, and the great Necessity of its Existence proved.

49. The Authorities taken from the Writings of Great Men no valid Objection against this Doctrine.

50. Its real Existence proved by an Experiment.

51. Further confirmed by another Esperiment.

52. Of its action upon the Rays of Light in their passing thro' different Mediums.

53, 54. From what Principle the same proceeds; namely, its different Degrees of Rarity and different Dinstances from Bodies.

55. Of its great Rarity and Elasticity, and the Proportion it bears to that of our Air.

56. Of the Subtilty of its original Atoms, and the great Conducement of the same to the elastick Property of the Aether.

57, 58. The same applied to Bodies as consider'd the natural Cause of Attraction and Repulsion.

59. The Impossibility of its proceeding from any Thing else proved and demonstrated.

60. The Manner how the Aether becomes the Cause of the sama more fully explained.

61, 62. Attraction of Cohaesion, what; with the Manner of its Action mechanically explained.

63. The Pulsion arising from the Aether is able to account for all the Phaenomena relating to the said Law of Attractisn of Cohaesion.

64. Of the Difference between a hard Body and a dense Body.

65, 66. Of the Properties of the Loadstone, and how they are caused by the same Aether; as also of Electrical Attraction arising from the same Cause.

67. Of Elasticity, its Nature and Cause.

68. Of the Spring and Nature of an Animal Fibre.

69, 70. Of Musick and Harmony, and how far that owes its Cause to the Aether.

71. Of the Nature of Force, and Cause of the Laws of Mechanicks, etc.

. II. Of the Law of Gravitation.

72. AETHER the Cause of Gravitation likewise, by means of the Sun; of the Sun's Magnitude, Rotation, Situation, and Illumination; and of the Cause of the same.

73. Of Mercury's Density, Motion, Situation, etc.

74. Of the like Particulars belonging to Venus, and of her Moon.

75. Of our Earth, and the several Particulars belonging to her.

76. Or Mars.

77. Of Jupiter.

78. Of Saturn.

79. Of the Comets, and their Uses.

80. Of all the Fixed Stars.

81. How to know their Distance from us.

82. Of the Moon.

83. Of her Motion, and of the Tides caused by it.

84. The Reason why the Planets often disturb one anothers Motion by attracting each other as they move along their Orbits, and which causes the Sun to be restless at some Distance from the common Center of our System.

85. Of the Moons belonging to Jupiter and Saturn.

86, 87. Of the Elliptical Figure of the Orbs of the Planets, and the Cause of it.

88. Of the Inclination of the Planes of those Orbits to the Plane of the Equator of the Revolution of the Sun round his Axis, and why they differ among themselves.

89. This fully answered.

90. Of the inclination of the Axes of the Planets to the Planes of their own Orbits, and of Mercury.

91. Of Venus.

92. Of Mars.

93. Of Jupiter.

94. Of Saturn.

95. Of the Spheroidal Form of all the Globes, and the Reason for the same.

96. A particular Table of the Distances, Magnitudes, Densities, and all the other Particulars relating to the planets, calculated.

97. Some further Remarks on the same; and first on Mercury, and all the nice Circumstances attending his particular Distance from the Sun.

98. Of Venus.

99. Of our Earth.

100. Of Mars.

101. Of Jupiter.

102. Of Saturn.

103. Of the Comets.

104. Of their suitable Magnitudes.

105. Of their peculiar Densities, and first of Mercury's.

106. Of Venus's.

107. Of that of our Earth.

108. Of Mars's.

109. Of Jupiter's, and his Inhabitants.

110. Of Saturn's, and his Animals.

111. Of the Moon.

112. Of the Sun.

113. Of the inclination of all their Planes to that of the Ecliptick, and first of Mercury.

114. Of the several Inclinations of their Axes to their own Planes, and the Intention of Nature in the same.

115. Of their several Motions, annual and diurnal, centrifugal, and centripetal, and first of Mercury.

116. Of Venus.

117. Of our Earth.

118. Of Mars.

119. Of Jupiter.

120. Of Saturn.

121. Of the Moon.

122. The Sum of the Whole, with the Physical Reasons for all these Things.

123. Gravitation itself, what; and the Opinion of others concerning the Cause of it.

124. More to the same Purpose.

125. Last of all the Author's Opinion of the same.

126. His Account of Aether and its Nature, and the Manner how it becomes the Cause.

127. Of the Extension and Properties of this Aether.

128. An Objection of Weight against the same answered.

129. A brief Account of the Creation, and of its original Principles out of which it was made.

130. How Matter first constituted various Bodies.

131. How some Bodies became solid Masses, and others only fluid Substances.

132. Aether the chief and ultimate Cause of all Natural Effects under God, and Nothing else can be so.

133. The great and many Advantages attending this Doctrine.

134. Of Astrology, and whether there be any Truth or Reason in the Study of it.

135. How far it is possible for the Stars to affect our Bodies and Minds, and after what Manner they do so.

136. A right Reflection on the empty Study of Astrology.

137. Aether how it acts upon Animal Bodies by means of the Planets, and especially by the Moon in affecting our Frame, mechanically accounted for: With thirteen Corollaries or Inferences of true Matters of Fact proceeding from this beautiful Doctrine of Aether, and a Conclusion to the second Head.

. III. Of Immaterial Substances.

138. The Author intends not hereby to solve all Things into Matter only, as some Philosophers most absurdly have done.

139. To prevent any such like Imputation or Reflection of any one, he hath ventured to say somewhat to the contrary.

140. The Intention and Design of the wise Being in the Formation of this World.

141. He hath ever since left it to be guided by those very Laws he had appointed for it at the Beginning, which Laws are already explained by us.

142. God has made Nothing new since then, but hath ever since ceased from all Works of Creation, and let the supernatural Effects of Nature to the Management of his Angels; and there is no Miracle but what they have a Share in the performing it.

143. Bad Angels can perform Miracles for the same Reason that good Angels can. A Miracle, what it is; and how far Nature is concerned in the Production of them.

144. The Manner how God may act in his private Providence, and yet not interrupt Natural Causes.

145. A like Case answered.

146. An Objection of some Men, who believe no such Beings as Angels and Souls of Men, answered, and the Existence of both clearly proved: With some few brief Remarks on a Pamphlet lately published by a certain Anonymous Author: Entitled, A philosophical Enquiry into the Physical Spring of Human Action, and the Immediate Cause of Thinking.

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Si judicas, cognosce.


I. MATTER and Motion are the two grand Principles of all Natural Philosophy, and make up the very Nature and Existence of the whole Universe; they are the Subjects of the Philosopher's Enquiries, and their Laws are the Causes of all Natural Phaenomena. [...]

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John Cook is said to be, in the first page of this book (London, MDCCXXXIII), the "Author of the Anatomical and Mechanical Essay on the Animal Oeconomy in one View, Ec.". In G.N. Cantor, "The theological significance of ethers" (contained in Conceptions of ether - Studies in the history of ether theories 1740-1900, Edited by G.N. Cantor and M.J.S. Hodge, Cambridge University Press, 1981) we can find (pp. 136-137) some information about this work, and its author:

"A more common claim concerning the significance of ether for natural theology was hat it was the principal secondary cause by which God governed the normal operations of the universe. For example, for John Cook, an Essex doctor, the discovery of ether was the key referred to in the title of his book [...] In this book he claimed that God employed ether as the immediate cause of all motion:

'AEther is the Rudder of the Universe, or as the Rod, or whatever you will liken it to, in the Hand of the Almighty, by which he naturally rules and governs all material created Beings ... Now how beautiful is this Contrivance in God'. (pp. 284-286)"

We can add since now a further quotation from Cook's book, always connected with this same point of view (pp. 347-349):

"I will next explain, after what manner these immaterial, thinking Beings can alter the known and stated Course of Nature , whenever their supream Lord wills any Thing of that Nature to be effected. [...] these Miracles, it is also my Opinion, were effected by Means of natural Instruments [..] as, for Instance, when Iron swam upon the Surface of the Water, it was a real Miracle to the Beholders, because not according to the usual, constant, and stated Law of Nature; (and that I call a Law of Nature, which is always the same, at all Times, except upon such extraordinary Cases, which I call a Miracle.) Now, tho' it was a real Miracle to Man beholding it, yet it was none to the Angel who did it; for he might do this, by supporting, for that Time, the pulsive Force of the Aether, or by suspending the Cause of Gravity, whatever be the Cause thereof; and then the Iron would swim, according to the Law of Nature that would follow upon such a Change".

[These last lines, with their frequent use of Italics, reproduce exactly the real typographical style of the book, while on the contrary the other ones previously reported do not.]