242 
POPULAR SCIENCE REVIEW. 
I turn next to the consideration of the plans of the various 
nations taking part in the observation of the transit of next 
December. 
To America, I conceive, the pride of place must in all fair- 
ness he conceded. She might reasonably have contented 
herself with but slight efforts on the occasion of this transit 
(because the transit of 1882 will fall pre-eminently to her 
share). But the American Government has voted a sum 
(30,000£.) twice as great as that which has been granted by 
the British Government* for the purpose. Then, as I have 
already mentioned, America has undertaken the most difficult 
of all the tasks which the proper observation of the transit 
rendered necessary, — I mean the occupation of the Crozets. 
Moreover, the preliminary investigation of the conditions of 
the transit by American astronomers is altogether excellent, 
contrasting strongly with the pretentious but blundering 
manifesto published by the official astronomers of a great 
nation, which shall be nameless. 
I have before me as I write the series of charts published by 
the Commission appointed to investigate the circumstances of 
the transit. These consist of four finely-executed stereographic 
charts showing that hemisphere (and a fringe beyond) on the 
earth which is turned sunwards at the time of (1) ingress 
exterior contact, (2) ingress interior contact, (3) egress interior 
contact, and (4) egress exterior contact. On these charts are 
marked two series of curves, one carried through points where 
the contact occurs at the same instant, and the other carried 
through points where the contact occurs at the same part of the 
sun’s limb. After a careful study of each chart (a study as 
careful as that which I gave to the Astronomer-Royal charts in 
1869), I am able to pronounce them singularly accurate for 
the degree of approximation which the authors claim.f 
The American astronomers are disposed to rely chiefly on 
* It must be noted, however, that our Government unhesitatingly granted 
all that the Astronomer-Royal asked, so that it would be altogether unfair 
to accuse the British Government of stinginess in the matter. 
t There is a very elaborate investigation of the error actually arising from 
the use of circles for the time-curves in the projection, to represent curves 
which are not in reality circles of the terrestrial sphere. The maximum 
error is found not to be more than 12', which, says the author of the paper, 
“ having regard to the scale on which the charts have been constructed, may 
be considered as within the unavoidable errors produced by imperfection of 
drawing.” The maximum error is four times as great when the curvature 
of Venus’s shadow-cone is altogether neglected in the usual way, according 
to which the resulting time-error is always of one sign. In the American 
charts the error is so distributed as to be positive or negative according to 
circumstances. 
