20 
POPULAR SCIENCE REVIEW. 
already understand how extremely difficult it is to obtain accurate 
and certain results. The infinite number of meteor-streams, and 
their great feebleness in general, and the difficulty of avoiding 
error in recording the path- directions of shooting- stars, and 
ascribing them their true radiants, all render the subject very 
complicated, and are a source of constant embarrassment to the 
observer. Moreover, the frequent impediments offered by 
cloudy weather and moonlight prevent anything like extensive 
observations being obtained during a single year, though a 
person constantly on the alert for all available opportunities 
ought certainly to register between 4000 and 5000 meteors in 
the course of twelve months, presuming that he worked all 
night long, and that the period of his observations was 
ordinarily favourable in point of weather. But extensive work 
of this kind is almost useless, unless it is thoroughly reliable. 
Even slight errors in mapping the meteor-paths bring about 
great discordances, and introduce confusion into a subject the 
nature of which is confused. The radiant points, deduced from 
hastily- gathered materials, appear to be extended over con- 
siderable areas of the sky, and cannot he determined with the 
necessary precision. It is a good plan, and one likely to con- 
duce to correct results in observing meteor-flights, to project a 
perfectly straight rod or wand (held in the hand for the 
purpose) upon the apparent course of a meteor directly it is 
seen, and then, noting the path exactly, it may be transferred 
to the star-chart. By this method the true direction is very 
closely represented, and it is necessary to adopt some such means 
of aiding the eye, which often fails to retain more than an 
approximate idea of the apparent course amongst the stars. 
The proposed plan so far facilitates precision, that in the case 
of swift, streak-leaving meteors the paths may often be registered 
with instrumental exactness, for in the moment that the streak 
lingers on the course, the wand is projected upon it, and the 
line of flight carefully noted and accurately reproduced on the 
star-map. 
It is only by the exercise of the utmost attainable accuracy 
that the numerous distinct showers visible every night of 
the year may be disconnected from each other, and their radia- 
tion-centres ascertained. Observations continued all night, or 
during at least four or five hours, are very valuable in this 
connexion ; for the majority of the showers are of such extreme 
tenuity, that during a short watch of, say two hours, no sign 
of their operation may be evident. It is to long-continued 
and accurate observations that we must look for important 
results, and for the final solution of the difficulty presented by 
the apparent long endurance of meteor-showers. Records of 
stationary meteors (/. e. } meteors whose direction of motion 
