i , ‘Apellgy orthblonicrtst on the Re afiabtions.” 
as fe a the zenith-distances 90° and 89°, bar. 30 and 
Z.D. 90° Z. D. 89° 
36051” 20” 2” 
Biv 36 17 25 50 
be ee. 34 12 
And saeh differences must always occur, unless some general 
principles be adopted, or some general mode of solution can be 
found out. 
Allow me, sir, hefore I conclude, to say a word about the 
"nd “ Concessions ” in your Mag. for last November. It is not easy 
ae to state. distinctly what is conceded and what is withheld. The 
sie balance ‘seems to be poised with a very even hand, between the 
¢ essions to be made, and the tone of authority to be kept up. 
it presume to give an opinion, I would say that the only 
error am now charged with, relates to my number ‘00419 which 
he makes 00416 ; amounting to +,,2,-55 of an inch, if we speak 
eel absolutely ; 3 or, relatively as my untagonist takes it, to ;4, of 
the existing quantity. There is some refinement in this way of 
2 reckoning ; for the less the quantity, the greater the error. I am 
sure there is nobody who has attended to the controversy, but 
will, allow that the chance of an error in his nnmber is greatly’ 
in my favour; ; but the whole difference is so very little, and he 
has already deseanted upon it so amply, that it would be a pity 
~ to add another word upon the subject. Besides, we shall soon 
have a table of surpassing accuracy; when he has spent his money 
in hiring a host of computers to complete his lucubrations. 
‘Thave some consolation, sir, in thinking that the discussions, 
in your work, on the subject of the refractions, will be found not 
altogether unimportant or uninteresting to the astronomer. I 
allude to the general view of the problem in your Magazine for 
May last, and to the formulse for the mean refractions in the 
same, and the following, number; to the observations made on 
the hypothesis of Cassini; and particularly to the remarks on 
Mayer’s formula in the Magazine for November. Since writing 
that article I have looked into the Fundamenta Astronomie of 
Professor Bessel, who is the only author I have met with that 
| does justice to the astronomer of Gottingen. In speaking of the 
correction for the thermometer, he thus expresses himself, p.26, 
** Ceterum in hoc quoque capite non equales solum, verum 
etiam posteriores astronomos antecessit Tobias Mayer, in re- 
fractionis formula rectius adhibens thermometri correctionem ; 
utrumobservationes an theoria eum huc perduxerint latet: ced 
confitendum est, correctionem illam postea inutilem atque falsam 
judicatam ejusque auctorem vituperatum esse quod eam calculis 
we inseruerit, 
