1871.] 



Anniversary Meeting. 



47 



double-image prism was placed between the eyepiece and the eye. The 

 prism was brought into four different positions 90° apart. At each posi- 

 tion of the prism an attempt was made to estimate the relative brightness 

 of the two images. The power of the prism was just sufficient to give two 

 images of the comet without their overlapping. The difference in bright- 

 ness of the images was exceedingly small ; I could not be certain that any 

 appreciable difference really existed. However, I attempted in each case 

 to select one of the two images as the brighter one. Afterwards I deter- 

 mined the position of the prism at the four different estimations, and I 

 then found that three of the estimations were in accordance with a portion 

 of the comet's light being polarized in a plane passing through the sun, 

 and one in opposition to that supposition. I hesitate to attach any posi- 

 tive value to these observations ; but they may perhaps be taken as show- 

 ing that no considerable part of the comet's light is polarized. 



The foregoing observations appear to show that the spectrum of this 

 comet is identical with that of Comet II. 1868, a description of which I 

 had the honour to present to the Royal Society*. 



It is worthy of notice that the cometary matter appears drawn out and 

 diffused towards the sun, and that it has not yet come under the influence 

 of the force, or been subjected to the conditions, whatever they maybe, by 

 which in most cases cometary matter appears to be powerfully repelled 

 from the sun. 



The observations were made with the telescope belonging to the Royal 

 Society, of 15 inches aperture. The spectroscope contained one prism with 

 a refracting angle of 60, and the small observing telescope magnified six 

 times. 



November 30, 1871. 



ANNIVERSARY MEETING. 



General Sir EDWARD SABINE, K.C.B., President, in the Chair. 



Dr. Blakiston, for the Auditors of the Treasurer's Accounts on the 

 part of the Society, reported that the total receipts during the past year, 

 including a balance of £127 9s. 3d. carried from the preceding year, and 

 56706 1 7s. 2d. balance of the Oliveira bequest, amount to ,£5095 15s. 7d. ; 

 and that the total expenditure in the same period, including 56518 2s. 10c?. 

 from the Society's funds to complete the payment for the Equatorial 

 Telescope, amounts to 565169 13s. 2d., leaving a balance of ^628 2s. 2d. 

 in the hands of the Treasurer, and of £101 19s. 9d. due to the 

 Bankers. 



The thanks of the Society were voted to the Treasurer and Auditors. 

 * Phil. Trans. 18G8, p. 555 and plate xxxiii. 



