Boscovich’s account of his vitrometer, 1767

Boscovich’s account of his vitrometer, 1767


Boscovich's account of his vitrometer, used for measuring and comparing with sufficient accuracy the refractive and dispersive qualities of prisms and lenses, 1767



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BOSCOVICH, Roger Joseph. De recentibus compertis pertinentibus ad perficiendam dioptricam, pp. 169-235 and 2 plates in: De Bononiensi Scientiarum et Artium Instituto atque Academia, Commentarii, Vol. V, Pars Prima. [With:] De unione colorum aliorum post alios per binas substantias, ac unione multo majore per tres, pp. 265-333 and one plate in Ibid., Vol. V, Pars Altera. Bologna: Typis Laelii et Vulpe, 1767

First edition, in two complete journal volumes, of Boscovich’s invention of the vitrometer. “In this dissertation, [De recentibus] . . . for the first time we find the description of the water prism known as the ‘vitrometro’ whose construction was carried out under Boscovich’s supervision for the purposes of measuring and comparing with sufficient accuracy the refractive and dispersive qualities of prisms and lenses. The knowledge of these quantities was, and is in fact, at the basis of the theories of achromatic and aplanatic objectives, and it allowed the determination, on knowing the curvatures of one or more lenses, the determination of those of the others . . . In [De unione colorum], Boscovich presented and discussed in substance the results he had obtained in the determination of the refractive and dispersive qualities of crystals and prisms with the water vitrometer, even though in the same dissertation he mentioned the use of the rectilinear and mixed-linear prism (that is, the curvilinear prism), and announced the use of the variable prism. It is quite important to underline the fact that in this dissertation Boscovich mentioned a substantially new criterion for the use of the vitrometer . . . Boscovich also provided a new, simple theory for the calculation of refractive qualities . . . [which] is not only in practice simpler and more certain than the previous one, but can also be applied directly to observations made even with the new variable prism . . . It is impossible to establish precisely when the first vitrometer was built, as Boscovich himself stated, by Giovan Stefano Conti and Abbot Niccolao Narducci, Conti’s friend and close collaborator. On the other hand, the ‘machinetta’ was really used, as can be seen from a letter Boscovich wrote to Conti in August 1763, in which Boscovich sent his friend the first results of calculations of measurements of the refractive and dustractive qualities” (Proverbio, ‘R. G. Boscovich and the measurement of the refractive quality of lenses,’ Memorie della Società Astronomia Italiana 60 (1989), pp. 837-888).

“John Dollond was apparently the first to try to correct secondary spectrum by the introduction of a third lens in his object-glasses, but he did not publish his result. R. J. Boscovich, a Jesuit professor at the University of Padua, entertained similar ideas and devised an instrument which he called the vitrometrum for investigating residual dispersion” (King, History of the Telescope, p. 158).

Two vols, 4to. Contemporary vellum with brown lettering-pieces on spines.