Lenses and Waves

1655-1672 - DE ABERRATIONE 83
speculations. What I have done is only what, in a small time, my thoughts did suggest,
and I never had opportunity of any experience.” 133
Barrow was too humble about his mathematical abilities but he was right in
observing that Huygens had more ‘experience’ in dioptrical matters. Huygens
praised Barrow in a letter to Oldenburg of 22 January 1670, but added “…
someday you will see that what I have written about it is completely
different.” 134 Yet, he did not hurry. The publication of Lectiones XVIII may
have pushed his plans to the background.
In February 1670 Huygens fell ill and he went to The Hague in
September, with an explicit ban by his physician to engage in intellectual
labor. In June 1671 he returned to Paris. Huygens’ dioptrics are not
mentioned among the manuscripts he entrusted to Vernon in February 1670,
when he feared the worst. 135 In Holland, he was with Constantijn again and
we may speculate that they also discussed dioptrical matters. In general,
Huygens wrote little about dioptrics in these years. He exchanged letters with
de Sluse on Alhacen’s problem, a mathematical problem regarding spherical
mirrors. 136 Much of his correspondence was taken up by a discussion about
the laws of collision he had sent to Oldenburg. No trace is found that
Huygens worked on executing the design of February 1669. Not long after
his return to Paris in June 1671, Huygens received a letter that would
eventually mean the end of his plans.
3.2.3 NEWTON’S OTHER LOOK AND HUYGENS’ RESPONSE
The invention of February 1669 is found on two places in Huygens’
manuscripts. One is his notebook of that period, the other is in the folder
also containing ‘Adversaria’ and seems to be the original calculation. 137 Both
contain the sketch of his invention and the ‘EUPHKA 1 feb. 1669’. In the last
one, however, the EUPHKA is crossed out and a ‘P.S.’ is added: “This
invention is useless as a result of the Newtonian aberration that produces
colors.” 138 Along with his invention, Huygens discarded all parts of De
Aberratione dealing with the improvement of telescopic images, namely his
earlier invention and his rules for the opening of keplerian telescopes. He
tore them from his manuscript and put them in a cover which said: “Rejecta
ex dioptricis nostris”. 139 The P.S. is dated October 25, without a year, but it is
likely to be 1672. 140 Evidently, this drastic decision was occasioned by the
preceding correspondence with Newton on colors.
133
Rigaud, Correspondence II, 70.
134
OC7, 2-3. “… vous verrez quelque jour que ce que j’en ey escrit est encore tout different.”
135
OC7, 7-13; especially 10-11.
136
Discussed in: Bruins, “Problema Alhaseni”.
137
Hug2, 72r and Hug29, 87r respectively.
138
OC13, 409n2. “Hoc inutile est inventum propter Abberationem Niutoniana quae colores inducit.”
139
OC13, 314n1.
140
The editors of the Oeuvres Complètes date it 1673, but in a conversation Alan Shapiro and I came to the
conclusion that it must have been 1672. I will return to this on page 92.