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XXVIII. On the discordances between the Sun’s observed and 
computed Right Ascensions, as determined at the Blackman- street 
Observatory ,in the years 1821 and 1822 ; with Experiments to 
show that they did not originate in instrumental derangement. 
Also a description of the seven-feet Transit with which the obser- 
vations were procured, and upon which the experiments were 
made. By James South, Esq. F. R. S. Communicated 
June 1, 1826. 
Read June 8, 1826. 
In presenting to the Royal Society the following pages, I 
am well aware that some apology is necessary ; the subject 
however to which they refer being intimately connected with 
the progress of astronomy, I am induced to hope that the 
Society will still receive with indulgence, what would long 
since have been communicated to them, had other astronomi- 
cal pursuits allowed me the opportunity. 
That the sun’s right ascension, found by observation, fre- 
quently disagrees with that afforded by calculation , astrono- 
mers I believe now generally admit ; an opinion however has 
been as generally entertained, that the discordances were the 
results of instrumental inaccuracy, occasioned by the effects of 
the solar rays upon certain parts of the instrument ; hence 
observations of the sun have fallen into disrepute, whenever 
an accurate knowledge of the time is the object of research. 
As, however, there is nothing which more impedes the 
advancement of science, than opinions too hastily adopted, 
it may be worth while to inquire whether practical astronomy 
