e 92 
tended over nearly three years ;—if northern observations 
had accomplished half as much in correspondent observa- 
tions, the question must be decided, and the celestial unit of 
measure determined with new precision. 
What shall I say, Gentlemen of the Academy, of Gilliss’s 
emotions, when, after returning from his long absence to com- 
bine and discuss the result of his five years’ labor, he found 
the following correspondent observations awaiting him ? 
From the Washington Observatory, — eleven of Mars, of 
which six were recorded as wholly, and three others as par- 
tially unsatisfactory, and eight of Venus, two of which were 
noted as bad. From the Cambridge Observatory, — five 
of Mars, of which four were of one limb only. From the 
Greenwich Observatory, —four of Mars, three of them being 
designated as not good. From all other Northern observ- 
atories, none. His expedition was fruitless, so far as his 
primary object was concerned, but the consciousness was his, 
that he had done his duty. 
He caused his results to be elaborated, thoroughly dis- 
cussed, and all possible observations in the Northern and 
Southern Hemispheres to be collected and combined. No 
toil was spared in this work; and the recollection of the pain- 
ful struggles to attain, through punctiliousness of computa- 
tion, what had been hoped for from abundance and thor- 
oughness of observations, is yet among the most vivid 
within the range of my memory. But it was in vain. The 
processes of reduction, the reference to approximate ephe- 
merides, the determination of the comparison-stars, are al] on 
record, and it will be for the future historian, when the true 
_ values are established beyond question, to decide whether & 
_ better” ein from the materials pro- 
vided. 
sults attained that from the second op- 
iia ett 
‘ 
