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XXIII. On the means of facilitating the observation of distant 
stations in geodcetical operations. By Lieutenant Thomas 
Drummond, of the Royal Engineers. Communicated April 
14, 1826, by Lieut. Colonel H. Colby, F. R . S. 
Read May 4, 1826. 
Xn consequence of the Report of a Select Committee of the 
House of Commons in June 1824, it was resolved, that a new 
Survey of Ireland should be immediately undertaken. 
The necessity of carrying on this extensive work with the 
utmost degree of rapidity, consistent with accuracy of exe- 
cution, being strongly urged in the Report to which I have 
alluded, the arrangements were directed to be made on a 
suitable scale, and every method to be adopted that seemed 
likely to contribute to this end. The triangulation, as form- 
ing the basis of the survey, and the means of accelerating its 
execution, claimed immediate attention ; and I was directed 
by Colonel Colby, at that time actively engaged in making 
the necessary preparations for this important undertaking, 
to consider by what means our distant stations might be 
rendered more frequently observable than the state of the 
atmosphere usually permits. 
From this source, at least in this country, arises the chief 
delay in carrying on such operations ; and the experience of 
a previous season among the Western Islands, had shown 
the probability of this impediment being materially increased, 
and more than ordinary difficulty encountered, in effecting 
