10 
POPULAR SCIENCE REVIEW. 
Large openings may result, so that the lower strata become ex- 
posed, or even the actual surface of the planet itself rendered 
visible through the fissures. It would be strong evidence in 
support of the latter thesis should the fact of recurrent bright 
markings be fulty established by further observations ; for it 
will be impossible to explain them on other grounds than that 
they are physically connected with the planet. Temporary 
obscurations will be accounted for by atmospheric inter- 
ferences. 
The phenomena of the dark and red spots in regions of the 
north and south hemispheres may also possibly receive a 
similar explanation, though we require a mass of well- authenti- 
cated records before the solution of the question can be satis- 
factorily brought about. A series of reliable drawings re- 
presenting the telescopic features of the planet at each ensuing 
opposition would, if extending over many years and executed 
by the same hand and instrument, be extremely valuable in 
such an investigation. A systematic scrutiny of the planet 
might be undertaken by a band of observers acting in unison, 
and the results accruing each year carefully registered for 
future comparison. Markings, if recurrent, would then be 
revealed in time, and their periods ascertained. It is true that 
drawings by different observers often show much dissimilarity ; 
but this should not, in the case where a large number are avail- 
able for comparison, have an unfavourable effect upon the dis- 
cussion, because the different styles of depicting details must 
soon become apparent and might be allowed for throughout the 
series. Thus the sketches would become readily comparable, 
and admit of such mutual corroborative testimony as the subject 
allowed. Observers engaged in a work of this kind must, 
however, exercise extreme caution in representing the details 
just as they see them, and not allow their imaginations to 
influence them in the slightest degree. On bad nights, when 
definition is execrable and the interesting features of the 
planet blotted out, nothing should be attempted. It will be 
better to wait for more favourable conditions of atmosphere 
than to make an effort to reproduce what can, at the- best, be 
very uncertainly seen, and what may prove an ultimate source 
of discordance and error. 
The diminutive pictures of Jupiter which we are accustomed 
to see in popular works on Astronomy and in scientific serials, 
should give way to sketches of larger dimensions. It is impos- 
sible that the details can be suitably and adequately repre- 
sented in drawings obviously too small for the purpose for 
which they are designed. It is true there is considerable diffi- 
culty in depicting this planet with all the details visible at a 
certain time ; his swift axial rotation originates a rapid change 
