384» Scientific ^ Intelligence. 
quires that the tube, especially at its extremities, should be so 
firmly fixed to the circle as to form one piece with it. In order 
to do this, connecting braces are attached at each end of the te- 
lescope. In progress of time, however, these braces have be- 
come insecure, owing to the screws which fastened them having 
given way. Hence the ends of the telescope are permitted to 
bend from the centre, instead of retaining an invariable position 
with respect to the circle. In the zenith this error is a mini- 
mum, and increases from the zenith to the horizon. This evil 
has now been remedied by Mr Troughton, who has applied addi- 
tional braces to connect the telescope with the circle. This 
alteration has already produced a great improvement in the ob- 
servations. Of the published observations, only those made in 
the three last months of 1819 are affected by the error. Du- 
ring 1820 the error increased, but, in the distance from the Pole 
to the Equator, did not amount to 2 seconds, at altitudes lower 
. than Sirius, and at the altitude of the sun at the winter solstice, 
the error may have exceeded 2 seconds, but did not exceed 4 
seconds. After the month of February 1821, the error rapid- 
ly increased, which ultimately led to the discovery of its cause. 
—See the Phil. Trans. 1822, Part I. p. 86, &c. 
5. Curious affearance observed on the Moon at the Cape. — The 
Reverend Fearon Fallows, the astronomer at the new observa- 
tory erected at the Cape of Good Hope, observed with his na- 
ked eye a whitish spot on the dark part of the moon’s limb. 
This happened on the 28th November 1821, about 8 o’clock p. m., 
when the moon was shining with a brilliancy which he had ne- 
ver observed in England. This spot seemed now and then to 
flash with consider^ible lustre. With an achromatic telescope 
about 4 feet long, magnifying 100 times, the spot seemed like a 
star of the 6th magnitude, and there were three others much 
smaller, but one of these was more brilliant than the one he had 
seen with the naked eye. The largest spot was surrounded by a 
nebulous appearance, but nothing of this kind was observed about 
the small brilliant spot. The two others were similar to faint 
nebulae, increasing in intensity towards the middle, but without 
any defined luminous point. As the telescope with micrometers 
had not yet arrived at the Cape Observatory, Mr Fallows had 
