Hence the necessity of presenting my work in two halves supplementary to each other may be compared to the necessity in consequence of which a chromatic object-glass, which cannot be made out of one piece, is produced by joining together a convex lens of flint glass and a concave lens of crown glass, the combined effect of which is what was sought.
Hortik dator nire obra bi erdi elkar osagarritan ematearen beharrezkotasuna, objektibo akromatiko batekin konparatzen dena, zeina pieza bakar batekin egitea ezinezkoa baita, crownglassezko lente ganbil batekin eta flint-glassezko lente ahur batekin osatzen baita, zeinen efektu bateratuak ezer baino lehen nahi dena lortzen baitu.