236 Transactions of the Royal Mieroscopical Society. 
I beg to direct the attention of the Society to the drawings, 
which feebly indeed and only very imperfectly display the phe- 
nomena, and which I have sent to the Secretary. The colours 
of the rainbow, beautiful as they are, entirely pale before the varie- 
gated and vivid intensity of solar miniatures thus examined. 
Fig. 1 represents the miniature of the house H, seen by the 
telescope in absence of sunshine. So soon as the sun comes out, 
the diffraction phenomena obliterate all the details of the house, so 
beautifully distinct before, as seen in Fig. 2. 
If now a miniature reflexion of the sun be arranged at the 
front door of the house, the instant the sun shines a similar effect 
is produced. Suppose, now, the condenser of a microscope be a fine 
ith, and the house be very much nearer, the miniature house, if 
white, can be beautifully examined by a good microscope ; but the 
instant the sun shines, the diffraction phenomena completely ex- 
punge the details before visible. 
So, whether considered telescopically or microscopically, destruc- 
tion of bright diffraction reveals new details invisible before. 
According to the brightness of the disk do the number of rings 
increase. I have seen eleven with the telescope, and above twice as 
many with the microscope. In the latter instrument they appear 
at almost exactly equal spaces apart, and gradually merge into 
coloured indistinctness. Whether the one or the other instrument 
be used, very perfect centering of the glasses can alone display the 
beauty and perfect truth of the deep jet-black tiny ring imme- 
diately surrounding the primary disk. The intensity of this black- 
ness, holding its own sharp form in the midst of a painfully bright 
effulgence, is perhaps the most marvellous of all the phenomena of 
the undulatory theory, and exactly fulfils the predicted condition 
of the inter cussating waves of the vibratiDg particles of the ether. 
The microscope has this enormous advantage, it is independent 
of external wind. I found the prism placed on a table when the 
sun was shining through an ordinary glass pane, developed all 
the phenomena with the utmost certainty. Not so the telescope. 
The air is seldom fit for these delicate observations, except at about 
7 A.M. in spring time. Kadiation is too abundant, irregular cur- 
rents abound, the forms of the disks are marred, and the diffraction 
lines become capricious and flickering. 
But once only have I ever observed the dark rings of the double 
star Castor in perfection. It was spring ; a London fog embrowned 
the sky as twilight advanced ; a still haze overspread the whole 
landscape ; the moon showed an absolutely steady atmosphere : it 
bore 500 with perfectly quiet definition ; the huge boulders, pro- 
fusely spread along the Apennine slopes, glittered distinct, and the 
shadows of caverns and mountains appeared as black as ink. 
Turning my 5J Wray equatorial on Castor with 500, each star 
of the double was surrounded with a perfectly depicted jet-black 
