U12 PHILOSOPHICAL TRANSACTIONS. [ANNO 1784. 



sisting of very different materials. A surface of a globe or map therefore will 

 but ill delineate the interior parts of the heavens. 



It may well be expected, that the great advantage of a large aperture would be 

 most sensibly perceived with all those objects that require much light, such as 

 the very small and immensely distant fixed stars, the very faint nebulae, the close 

 and compressed clusters of stars, and the remote planets. On applying the 

 telescope to a part of the via lactea, I found that it completely resolved the whole 

 whitish appearance into small stars, which my former telescopes had not light 

 enough to effect. The portion of this extensive tract, which it has hitherto been 

 convenient for me to observe, is that immediately about the hand and club of 

 Orion. The glorious multitude of stars of all possible sizes that presented 

 themselves here to my view was truly astonishing; but as the dazzling brightness 

 of glittering stars may easily mislead us so far as to estimate their number greater 

 than it really is, I endeavoured to ascertain this point by counting many fields, 

 and computing, from a mean of them, what a certain given portion of the milky 

 way might contain. Among many trials of this sort I found, last January the 

 18th, that 6 fields, promiscuously taken, contained 110, 60, 70, 90, 70, and 

 74 stars each. I then tried to pick out the most vacant place that was to be 

 found in that neighbourhood, and counted 63 stars. A mean of the first 6 gives 

 79 stars for each field. Hence, by allowing 15 minutes of a great circle for the 

 diameter of my field of view, we gather, that a belt of 1 5 degrees long and 2 

 broad, or the quantity which I have often seen pass through the field of my tele- 

 scope in 1 hour's time, could not well contain less than 50,000 stars, that were 

 large enough to be distinctly numbered. But, besides these, I suspected at least 

 twice as many more, which, for want of light, I could only see now and then 

 by faint glittering and interrupted glimpses. 



The excellent collection of nebulae and clusters of stars which has lately been 

 given in the Connoissance des Temps for 1783 and 1784, leads me next to a 

 subject which indeed must open a new view of the heavens. As soon as the first 

 of these volumes came to my hands, I applied my former 20-feet reflector of 12 

 inches aperture to them ; and saw, with the greatest pleasure, that most of the 

 nebulae, which I had an opportunity of examining in proper situations, yielded 

 to the force of my light and power, and were resolved into stars. For instance, 

 the 2d, 5, 9, 10, 12, 13, 14, 15, 16, 19, 22, 24,28, 30, 31, 37, 51, 52, 53, 55, 

 56, 62, 65, 66, 67, 71, 72, 74, 92, all which are said to be nebulae without 

 stars, have either plainly appeared to be nothing but stars, or at least to contain 

 stars, and to show every other indication of consisting of them entirely. I have 

 examined them with a careful scrutiny of various powers and light, and generally 

 in the meridian. I should mention, that 5 of the above, viz. the 1 (5th, 24, 37, 

 52, 67, are called clusters of stars containing nebulosity; but my instrument 





