Referee report by J. F. W. Herschel on 'Astronomical Experiment on the Peak of Teneriffe, Carried out under the Sanction of the Lords Commissioners of the Admiralty' by C. Piazzi Smyth

                                every possible elucidation) Mr. Smyth does not appear to have 
made any observations at either of his Stations.
6. The height and duration of twilight at Great Altitudes. Set
-tled by observations as definite as their nature admits. -
Where the success of the postulated observations has been wholly 
or in part defeated by local conditions, they have been the means 
of setting these conditions themselves in a very interesting 
light, and eliciting features of <s>very <\s> marked importance - thus 
1 The dip of the Sea Horizon from the higher Station (proposed 
by the Astr Royal) could not be observed - since no such 
Horizon could ever be seen from those Stations. But in lieu 
of an Astronomical Observation which would doubtless have 
a certain interest, we are presented with the grand Meteorological 
fact of a permanent, boundless & uninterrupted Ocean of 
Cloud at half the height of the trade currents, cutting off 
all view of the sea during the whole of the summer season 
- with an incumbent atmosphere of excessive hygrometric 
dryness. After Mr. Welsh’s Balloon ascents, these observations 
are definitive as to the habitual state of dryness of the 
upper regions of the atmosphere.
So also the observations of the fixed lines in the Solar 
Spectrum recommended from several quarters, would seem 
to have been thwarted by atmospheric peculiarities - <s>but<\s>
if indeed such an expression be applicable to results which 
open out quite a new field of enquiry into these phenomena,
by shewing them, and indeed the extent of the visible spectrum 
itself, to be far more dependent on atmospheric conditions 
than had been at all before supposed -
It is very much to be regretted that the Actinometric 
observations which would have been, if successful, of ex-
-traordinary value, should have failed from causes depen-
-dent