184 Researches on Solar Physics. 
and so on upwards to the present date. It is also our intention 
_ ultimately to publish carefully copied representations of each of 
the Kew groups; but these are not yet ready. We think it 
well, however, to give at once the numbers of the groups, 
also to make use of these numbers in our present paper in an- 
ticipation of the forthcoming pictorial representations, which, 
when they appear, will enable our readers to judge for them- 
selves of the truth of our remarks. : 
[The table and some comparisons of the Kew observations 
with those of Sehwabe are omitted.] 
$V. Two classes of investigations. 
18. Our investigations may be divided into two classes: 
(1.) Those in which remarks are made regarding the behavior 
and appearance of spots and facule, and generalizations deduced 
therefrom, which do not involve aceurate measurements. ; 
(2.) There are, however, certain results in order to obtain 
19. Correction for solar atmosphere—The most important of 
these is the correction due to the refraction of the solar atmos: 
phere, which Carrington has indicated, but without applying it, 
in his large volume. There are evident proofs of the existence 
of such an atmosphere; f : 
(1.) In the Kew photographs the central portion of the disk 
uniformly indicates a greater luminosity than the borders, 28 if 
the rays at the borders had to pass through a large extent 0 
5 
