1870.] Astronomy, 523 



a point on the earth where the limbs of the sun and moon are in a 

 line; that is, where the eclipse is total exactly." In any given 

 total eclipse the coincidence of the limbs of the sun and moon is 

 necessarily a momentary phenomenon ; and the state of things at 

 the moment is altogether exceptional. What has to be explained 

 before Mr. Lockyer's strange theory can be admitted, is the observed 

 state of things when lines from the sun's limb to the moon's disc 

 fell eighty miles or so from the observer's station. Mr. Lockyer 

 himself has begun to recognize the necessity of explaining away 

 this difficulty, and he now supplements his theory by introducing 

 " a possible action at the moon's limb," though what the nature of 

 that action may be he forbears to indicate. 



Mr. Browning gives an account, accompanied with illustrations, 

 of his ingeniously devised automatic spectroscope referred to in our 

 last. When this paper was read before the Koyal Astronomical 

 Society, Professor Pritchard stated that he had given several hours 

 to the examination of the optical relations of the new instrument, 

 but could not definitely assert that minimum deviation is secured 

 for rays of all orders of refrangibility. Although the instrument 

 is probably as perfect practically as it can be made by whatever 

 further refinements may be adopted, it requires but little considera- 

 tion to show that it does not in its present form theoretically secure 

 true minimum deviation for all rays. The fixity of the first prism 

 (the collimator being also fixed) suffices to prevent this. We believe 

 that Mr. Browning is now at work on a modification of his instru- 

 ment which has been suggested to him, in which this objection is 

 obviated. 



Fr. Perry, of the Stoneyhurst Observatory, gives an account 

 of an observation made on Winneeke's new comet (discovered on 

 May 30, at Carlsruhe). He had searched in vain for D'Arrest's 

 comet. Mr. Hind sends the elements (calculated by Winneeke 

 himself) of the former comet, which is described as a round pretty 

 bright nebula, about 2J minutes in diameter. 



Lieut. Hill, on May 22, saw three large spots on the sun, with 

 the naked eye. On the following day a fourth spot was visible. 

 We believe that this is the first instance on record in which so many 

 spots have been seen without telescopic aid. 



In a paper on the stereographic projection, Professor Cayley 

 points out that the very same circles which in the direct stereo- 

 graphic projection of a hemisphere (viz. that wherein the projection 

 is on the plane of a meridian) represent the meridians and parallels 

 respectively — represent also in the oblique projection of the hemi- 

 sphere meridians and parallels respectively. 



Mr. Lynn discusses the proper motion of the star " Groombridge, 

 1830." He finds as the final result of his examination of the 



VOL. VII. 2 N 



