1. See Brown, Scientific Organizations, chaps. 4-6; Stroup, "Christiaan Huygens." Huygens, Oeuvres, vols. 3-8, 19, 22, and passim, reveal his work with Thuret, Papin, and others on air pumps, microscopes, and clocks. For an inventory of Picard's instruments, see AdS, Reg., 9: 198v-99r. [BACK]

2. Gunther, Early Science in Oxford, 6: 5, 22, 76, and passim; Ornstein, Rôle of Scientific Societies, 107-10; Middleton, Experimenters; Mariotte, Traitté de nivellement; La Hire, L'école des arpenteurs; Auzout, Traité du micromètre; Roberval, "Nouvelle maniere de Balance"; Huygens, "Extrait d'une lettre ... touchant une nouvelle manière de barométre." [BACK]

3. The Academy tested aerometer adapted from a design of the Florentine academy: Dodart, Mémoires des plantes, 188-91; see Hooke's comment in Philosophical Collections, 1: 39-40. Duclos used an aerometer, along with a compound balance, to analyze mineral waters: Observations, 198-201; discussed by Stubbs, "Chemistry at l'Académie Royale des Sciences," 90. Homberg experimented with an aerometer in his air pump: AdS, Reg., 16: 209r (31 July 1697). The enameler Hubin supplied and repaired aerometers for the Academy and probably also made its thermometers: BN MS. n. a. fr. 5147 records purchases and repairs. For a definition of "aerometer," see Furetière, Dictionnaire; for an illustration, see Historia, plate facing p. 389, fig. 2a, p. 439; for Homberg on the aerometer, ibid., 438-40. Academicians again adapted a design of the Accademia del Cimento when they used a thermometer to regulate the heat of distillatory fires; Dodart discussed apparatus in 1674 and 1675, but the amanuensis was unfamiliar with the words so that the instruments he named are unknown: Dodart, Mémoires des plantes, 180-81; AdS, Reg., 8: 7r, 3r, 4v. [BACK]

4. Borel, Observationum microscopicarum centauria, Obs. 6-8, 17, 19, 46, 63, 96, tried to identify atoms as proof of atomism and also examined the exteriors of plants; he was not interested in plant anatomy. Hooke described the cellular structure of plants, while Henshaw found vessels in the wood of walnut trees: Hooke, Micrographia, 106; von Sachs, History of Botany, 229. In 1681 Schrader, De microscopiorum usu, summarized botanical and anatomical microscopy, citing Borelli, Swammerdam, Grew, Malpighi, Hooke, and others; he discussed the circulation of sap, 18-19, without mentioning the Academy's work. On the history of the microscope and its uses, see Turner, Essays, and Clay and Court, History. [BACK]

5. Roger, Sciences de la vie, 183-84. Dodart recommended using microscope and loupe to correct descriptions or illustrations of plants: BMHN MS. 450: 107r, 124. [BACK]

6. AdS, Reg., 1: 33:

Les Experiences sur la naissance des Plantes se feront en considerant les racines, et semences, et les examinant diligemment avec le Microscope soit avant que de les mettre en terre soit en les en tirant en divers temps pour considerer les differents Changements qui leur arrivent en la grandeur ou en la figure de leurs pores, en leurs sucs, pesanteur, couleur, odeur, saveur & c. Ensuitte on considera ce qui arrive a leurs germes quand ils commencent a pousser principalement a ceux qui sont enfermez au dedans des grandes semences comme on voit aux glands du chesne, ou on remarque la racine, le tronc et les Branches de tout l'arbre qui paroist desja formé et distingué avant que de sortir d'entre les deux parties esquelles le gland a acoustumé de se fendre.

Perrault used the terms "microscope" and "engyscope": ibid. and 36; see Furetière, Dictionnaire, for the latter. [BACK]

7. AdS, Reg., 8: 218r-v (Apr. 1678 to June 1679). See chap. 10, above, for La Hire's later views about the rise of sap. [BACK]

8. Ibid., 8: 156r (23 Mar. 1678): "du bled en herbe, dans lequel on voyoit tous les noeuds, et l'epic formé avec les grains commencez sur un tuyau de deux lignes de long." [BACK]

9. Ibid., 11: 1r (23 June 1683), 168v (6 Apr. 1686). [BACK]

10. Ibid., 4: 81r-v (7 July 1668); Mariotte, Végétation, 129, 130-32, 137-38, 143. He distinguished between fibers and filaments and argued that spongy matter adhered to the membrane; his plants and descriptions are different from Hooke's in Micrographia, 101-15. [BACK]

11. Mémoires, 10: 101-3, 120-22, 191-97, 406-15; Histoire, 2: 153-54 (1692). [BACK]

12. AdS, Reg., 7: 176r, 185r-v (16, 30 July 1678). On the history of spherical lenses, see Rooseboom, "History of the Microscope," 272; Daumas, Scientific Instruments, 45. Several savants described how to make and use the glass globules: see, for example, Huygens, "Extrait d'une lettre ... touchant une nouvelle maniere de microscope," and Oeuvres, 8: 90-93, 96-97, 113-14, 122-25, 128-29, 131, 187-88; 13, 2: 520-27, 680-85; Hartsoeker, "Extrait d'une lettre ... touchant la maniere de faire les nouveaux microscopes"; Hooke, Lectures and Collections ... Microscopium, 92, 97-98; Locke, Travels, 250. [BACK]

13. AdS, Reg., 7: 185r-v, 244v; Huygens, Oeuvres, 22: 269. [BACK]

14. AdS, Reg., 7: 244r: in sunflowers it resembled balls with rays; in wood sorrel (trifolium acetosum) it was round and pierced in the center; and in jonquil it looked like physic nut or croton seed (pignons d'inde). Du Hamel noted observations with Huygens's microscope in his annual report to Colbert: ibid., 8: 219r (Apr. 1678-June 1679). [BACK]

15. Huygens, Oeuvres, 8: 65, 106, 112 (quotation), 205, 213. [BACK]

16. Ibid., 13, 2: 699-700. [BACK]

17. A spherical lens was most appropriate for examining transparent objects, since any object had to be held very near the glass globule, making illumination difficult. Observers needed either a dark background or an oblique source of light, and Huygens developed interchangeable diaphragms to regulate the amount of light. A liquid was best seen when a drop of the liquid adhered to the glass lens. For holding other objects, Huygens preferred mobile glass slides to narrow tubes. See Hooke, Lectures and Collections ... Microscopium, 98-99; Huygens, Oeuvres, 13, 1: cxlii; 13, 2: 520-26; 8: 64-65, 212; Rooseboom, "Huygens et la microscopie," 61, 72nn. 22, 24-26. On the mounting of the glass globule, see Daumas, Scientific Instruments, 46-47. [BACK]

18. AdS, Reg., 7: 200r (20 Aug. 1678); Huygens, Oeuvres, 8: 92-93, 106, 112, 114, 123-24, 128-29, 130-31, 187-88. [BACK]

19. On the relative advantages of the various simple microscopes available at the end of the seventeenth century, see: Hooke, Lectures and Collections ... Microscopium, 96-97; Rooseboom, "History of Microscope," 270-71; van Cittert, "The 'van Leeuwenhoek Microscope,'" "The Optical Properties of the 'van Leeuwenhoek Microscope,'" and "On the Use of Glass Globes as Microscope-Lenses"; Rooseboom, "Concerning the Optical Qualities of Some Microscopes made by Leeuwenhoek." Huygens's spherical lenses probably had a magnifying power of 40x: Rooseboom, "History of the Microscope," 272. I am indebted to Gerard L'E. Turner for discussing with me the problems of late seventeenth-century lenses and for pointing out that any improvements made before the development of achromatic lenses in the eighteenth century would have been very modest. He is skeptical of the view that spherical lenses provided better images than ground lenses. [BACK]

20. The articles he wrote in his own and Hartsoeker's names for the Journal des sçavans stirred up interest, and he demonstrated the instrument outside the Academy to Colbert, his brothers, and "some learned men who live with them": Huygens, Oeuvres, 8: 91-92, 96-99, 100-103; Historia, 171. [BACK]

21. On Huygens's interest in microscopes and their uses, see Rooseboom, "Huygens et la microscopie," 59; Huygens, Oeuvres, 4: 334; 7: 315-16, 400, 417; 8: 21n. 2, 58-63; 22: 553, 564, 595, 599, 686, 698, 702. [BACK]

22. Phil. Trans. (11 Mar. 1666); printed in Boyle, Works, 3: 154-55; Gunther, Early Science in Oxford, 6: 245-46 (7 June 1665); 7: 493 (11 July 1678). See also 'Espinasse, Robert Hooke, 51, 171n. 21. Borelly thought the air pump had potential for chemical research: AdS, Reg., 11: 168v (6 Apr. 1686). [BACK]

23. AdS, Reg., 1: 256, 259-60 (17 Mar., 7 Apr. 1668); 4: 10r-v (21 Apr. 1668); Huygens, Oeuvres, 19: 200, 207; 17: 332. When Dodart referred in his 1676 Mémoires des plantes, 137, to academic studies of germination in a vacuum, he had in mind these tests made by Huygens between 7 April and 12 May 1668. On Huygens's development of the air pump see Stroup, "Christiaan Huygens." [BACK]

24. AdS, Reg., 4: 10v-11r (21 Apr. 1668); Huygens, Oeuvres, 19: 209, 211-12. Huygens reported his observations three weeks later, but the experiment lasted only eight days. Huygens put into the bell jar a device intended to show whether all the air had been evacuated; this was a tube five to six pouces long that was filled with water and placed with its open end in the same container of water that held the branch. [BACK]

25. AdS, Reg., 4: 19v-21r (12 May 1668); Historia, 58; Huygens, Oeuvres, 17: 312-14; 19: 211-12. Fontenelle elaborated Huygens's explanation. He asserted that all bodies contained air that could escape when external air pressure diminished. In an evacuated receiver, therefore, enclosed bodies would exhale an "artificial" air, whose characteristics varied according to its origin. Fontenelle supported his argument with the observation that a fallen column of mercury could rise in an evacuated receiver; to explain this, he cited the weight of newly exhaled air: Histoire, 1: 46-47. See also Marsak, Fontenelle, 19-22; Dijksterhuis, Mechanization of the World Picture, 4: 261-82. [BACK]

26. Huygens, Oeuvres, 22: 254; AdS, Reg., 8: 59v-60r (24 July 1675). Dr. N. B. Ward's similar observation of grasses in a sealed glass bottle from 1829 to 1833 led to the use of closed glass cases for oceanic transportation of rare plants; see Lemmon, Golden Age, 183. [BACK]

27. Boyle inspired Huygens to work on air pumps, and Huygens's first machine resembled the one Hooke had built for Boyle; Homberg's earliest inspiration was von Guericke, and in 1683 he used a pump made by Dalancé which was an improvement of von Guericke's: Mémoires, 10: 648, reprinted from JdS (1683); Histoire, 1: 361 (1683); see also Middleton, History of the Barometer, 355. By 1692, however, Homberg had made his own air pump, which resembled the machines developed by Hooke, Boyle, and Huygens: Mémoires, 10: 215, 256, 281 (fig.); compare Histoire, 2: 138. [BACK]

28. Mémoires, 10: 319-23. [BACK]

29. Ibid., 348-54; see AdS, Reg., 13: 135r-v (13, 17 June 1693). [BACK]

30. Mémoires, 10: 349-51. [BACK]

31. Ibid., 353-54; see also Histoire, 2: 187-88 (1693); Historia, 324-25 (1693). [BACK]

32. Mémoires, 10: 351-52. [BACK]

33. Ibid., 352. [BACK]

34. Ibid., 319-23, 353. For Homberg, "vapeur" was a mixture of ethereal matter with particles of water. [BACK]

35. Ibid., 354, 283, 259. Compare Dodart, Mémoires des plantes, 209; Histoire, 1: 47; 2: 170-72; Mémoires, 10: 529-36, reprinted from JdS (1672). [BACK]

36. Willis performed his experiment in 1669 and Plot published it in his Natural History of Oxfordshire (1677): Gunther, Early Science in Oxford, 3: 207-8. [BACK]

37. Huygens, Oeuvres, 3: 383-84; Birch, History of the Royal Society, 2: 29, 56, 419-21. [BACK]

38. Perrault, Circulation, 113. [BACK]

39. Histoire, 2: 207 (1694). [BACK]

40. Mémoires, 10: 348. [BACK]