146 Remarks on Dr. Enfield’s Institutes 
possess-an excess of refraction, without also possessing an 
excess of dispersive power? For the removal of this diffi- 
culty, no hint is given of the great fact which lies at the 
foundation of Dollond’s improvements, viz. that the dis« 
persive power of different media is not proportioned to 
their mean refractive power. Unless he has the sagacity 
to peor that this wired be the case from the minnie 
ate ro ie will 1 | ey once fo all, give the cor-. 
tho aS. ined 
sr 133, 137, hn 3985 read 3956. 
Prop. 3. Cor. 229: 2BI2F. 
Prop. 8. Schol. es 28° Bu (3820) 33097 57! 
Do. one degree 2° 42! 
Beep 35. sabnesieee eee CRANE ts septa SBOt SEM 
lemons: pa ete tg: Ske wet to, gain Ob Bt 
Prop. 61. Scho line 9. ninth snes et tonehe, 
; tS Seer ‘ d..h....m. 
Prop. 116.Schol. —‘1:18 28,6 1 18 27,6 
eke 118 Pe Bw he: 
7 3 59,6 of. BAe 
| 3 1618 5, 16 16 31,8 
Prop. 117. Cor.179, 182, 194,000, 000 190. ,000, 000 
* Delambre, Biayiale, Sates a &e. 
ee iene eee 
on These numbers are Flamsteed’s. ‘The corrections are given from Lap: 
