84 Scientific Proceedings, Royal Dublin Society. 
Nature’s OpERATIONS ON A LARGE SCALE. 
When we turn our attention to Nature’s operations on the 
large scale we find that the greatest lengths we can as yet succeed: 
in measuring are the distances of those few stars which have per- 
ceptible parallax.1 The distances of these stars from the Solar 
System range from four to fifteen metro-sixteens; and it is not 
likely that any star could send us light enough to be visible in any 
of our telescopes if a thousand times more remote. At a distance, 
then, of about ten thousand metro-sixteens, that is, at a distance 
of about a metro-twenty, our knowledge of the starry universe 
comes to anend. It is perhaps possible, that the great Nebula in 
Andromeda, and a few other non-gaseous nebule, are stellar sys- 
tems distinct from that of which the Milky Way is the outlying por- 
tion, and which is commonly spoken of as the stellar universe. If 
so, such of these other “‘ universes ”’ as can be visible to us probably 
lie within a sphere which extends into the space beyond our stellar 
system, perhaps some 100 times further than the boundary of the 
Milky Way, and may accordingly need, to represent the distances 
of some of them, numbers inserted in the next column of our table 
(fig. 6). Accordingly, the column of metro-twentyones is in the 
table indicated as one of those included within the range of what 
man possibly already knows something about. 
From this preliminary survey, it appears that man is only 
acquainted with a strictly limited portion of the scale upon which 
the real operations of Nature are being carried on. All her opera- 
tions upon an ultra-stellar scale, all her activities at infra-molecular 
degrees of proximity, are kept from our view by that heavy veil 
of Isis which man’s limited senses and his restricted intellectual 
powers cannot lift. It raises us in the scale of thinking beings to 
1 Attempts have been made to infer the parallax of binary systems from a spectro- 
scopic determination of the difference of velocity in the line of sight of the constituent 
stars, combined with the known periodic time and the apparent angular size and form 
of the system. This method has been applied to y Virginis and to the companion of 
ry Andromede with results which are not yet free from doubt on account of the extreme 
delicacy of the observations, but which seem to place these stars about one step of our 
scale farther, i.e. about ten times farther, from us than those of which the parallax 
can be directly measured. 
