Lenses and Waves

1655-1672 - DE ABERRATIONE 79
carry out the plan with an entire glass, like I have asked you to make for
me.” 114
During the following months, Huygens kept reminding his brother that
he was waiting for the proper lens. 115 He even considered taking up his own
grinding work and started looking around in Paris for able craftsmen. 116 On
November 30, he sent his brother additional directives for oculars. 117 On 1
February 1669, Huygens brought his invention to Constantijn’s attention for
the last time: “You don’t talk anymore about the oculars you have promised
me.” 118 This was the final, somewhat aggrieved sentence of a letter in which
he informed his brother of another letter – one he had received from a
certain baron de Nulandt, an acquaintance of Constantijn living in The
Hague at that time. 119 The baron was engaged in making telescopes and also
had some ideas regarding dioptrical theory. On 20 December 1668, Nulandt
had written to Huygens. In the letter of 1 February to his brother, Huygens
wrote:
“The worthy Baron de Nulandt begins to talk like a great savant, and lets me coolly
know that he has found the same proportions of glasses to imitate the hyperbola of
which I have talked to him in my letter, although I am sure that this is infinitely beyond
his capacities. The calculations he sends me are far from the truth, and I will not refrain
from showing him this.” 120
Huygens had told Nulandt about his idea of nullifying spherical aberration
by means of spherical lenses in a letter now lost. On 18 January, Nulandt had
replied that he had also found that a concave meniscus lens could correct the
aberration of the objective lens, but had not given any details. 121 In that letter,
Nulandt calculated the amount of aberration for two lenses and had drawn
conclusions that were contrary to Huygens’ own. Huygens’ letters in reply
are lost, but it is clear that he easily convinced Nulandt of his mistakes. In his
next letter, Nulandt admitted that his configuration for nullifying spherical
aberration was faulty, because he had calculated the aberration of lenses in a
wrong way. 122
114
OC6, 221. “mais devant que de l’assurer je serois bien aise de faire l’essay avec un verre entier, que je
vous ay priè de me vouloir faire.”
115
OC6, 236; 266. He did not show consideration for the fact that Constantijn was getting ready for his
marriage on 28 August 1668.
116
OC6, 266; 300.
117
OC6, 299-300.
118
OC6, 353. “Vous ne parlez plus des oculaires que vous m’avez promis.”
119
Little is known about him. He published an anti-Cartesian treatise Elementa physica in 1669 in which he
included an extract of a letter written by Christiaan (OC6, 420-421). He first appears in a letter to Huygens
of 20 December 1668, which suggests that they had met, probably in Paris. OC6, 304-305.
120
OC6, 353, “Le Seigneur Baron de Nulandt commence a parler en grand docteur, et me mande
froidement, d’avoir trouvè les mesmes proportions de verres, pour imiter l’Hyperbole, dont je lui avois
parlè dans ma lettre, quoique je sasche bien que cela passe infiniment sa capacitè. Les calcus qu’il
m’envoye sont trop eloignez de la veritè, et je ne manqueray pas de le lui remontrer.”
121
OC6, 348-351; particularly 350.
122 OC6, 363-367; particularly 364.