THE HAMBURG ACCOUNT OF WRIGHT'S THEORY. 185 



they are magnified, and through all glasses become more 

 dull than otherwise they appear to the naked eye. And 

 hence we may infer, without any further evidence, that 

 the stars are all light bodies endowed with native lustre; 

 and that bodies like the known planets, from the same 

 reasoning, it is as clear they cannot be, because their distance 

 would render them all in such a case invisible. A proof 

 of this will plainly present itself if we consider the course 

 of the known comets, who all of them, without exception, 

 become imperceptible and entirely disappear ; though most 

 of them much bigger than the earth or any of the lesser 

 planets long before they arrive at their respective 

 Aphelions. But we are under a kind of necessity to 

 believe them either suns or planets, that is, either dark 

 or light bodies ; and since I have shown the improbability, 

 nay, I may venture to say, the impossibility of their being 

 the first, it is natural sure to conclude that they must 

 be of the last sort." But to put the matter beyond all 

 controversy the author presents the following optical 

 experiment: "Place any concave lens before your eye, 

 and you will find all visible objects will appear through 

 it as removed to a much greater distance than they really 

 are at, and reciprocally as much diminished. Now if you 

 look upon one of these glasses of a proper concavity, 

 opposed to the sun or moon, you will respectively have 

 the appearance of a real star or planet, the first exhibited 

 by the body of the sun, the other by the moon, and 

 either more or less diminished in proportion to the surface 

 of the sphere the glass is ground to. For example, a double 

 concave, or glass of a negative focus, ground to a sphere 

 of about three inches diameter, will, if opposed to the 

 sun's disc at a proper distance from the eye, help you to 

 a very good idea how the sun appears to the planet 

 Jupiter ; and if a proper regard be had to the distance 

 of the planet Saturn, a lens still more concave may be 

 formed to give a just idea of the sun's appearance to 

 Saturn. Again, one much more [less] concave than the 

 former, proportioned to the orbit of Mars, will naturally 

 exhibit the solar body as seen from that planet." The 

 author next proceeds "to enquire what the real use and 

 design of so many radiant bodies are, or may be made 

 for. The sun," he says, "we have just reduced to the 



