Observations on Comet II. 213 



meters, to ascertain the direction of the tail, and also of the jet 

 from the nucleus, and having carefully observed these particulars 

 for about a quarter of an hour (the telescope being out of doors), 

 Mr. Howlett, re-entering his house, marks them down by 

 slightly scratching on black paper with a penknife, the paper 

 being supported on a pane of glass, and held before a lamp, 

 which renders the slightest scratch at once apparent. He then 

 repairs to the telescope, applies a higher power, generally 120, 

 and earnestly scans the comet till some new feature is fully im- 

 pressed on his mind. Then he returns to the lamp, and very 

 carefully notes down what he has seen. Sometimes ten minutes 

 are employed in making sure of a fact, and as long a time in 

 fitly representing it. Thus the drawing goes on till completed. 

 Any scratch de trop is rectified by a little thick ink applied 

 to obliterate it. These transparencies represent nearly the whole 

 comet ; but except in my tinted plate, I have copied only the 

 head of each. 



My own plan, though as different as might well be, I am 

 inclined to think is also very efficient. I place my telescope on 

 a table out of doors nearly opposite a window. Inside the 

 window stands a lighted candle, and in front of it a powerful 

 condensing lens (belonging to my microscope), placed at that 

 precise distance from the candle that it casts a narrow stream 

 of light to a great distance. I have a piece of card or paper 

 and a pencil on my table, and when I choose I can place the 

 paper in the brilliant light from the lens without allowing the 

 glare to reach my eye. My drawings, being done in pencil, 

 represent stars by black dots, and the brightest parts of the 

 comet by the darkest shading, but I frequently copy them at 

 once in imitation of the real appearance. 



Perhaps the two plans could be combined, and the black 

 paper and lamp conveyed to the open air; only that comets 

 take us by surprise, and we hastily improvise a plan, instead of 

 losing time by making many experiments. 



On the 19th, Mr. Dawes also observed the comet, and notes 

 that the nucleus was no longer so singularly sharp and distinct 

 as on the 3rd. From this time, the weather appears to have 

 improved, and many observations have reached me; but space per- 

 mits me to give few besides my own and those of Mr. Howlett. 



The comet, on the evening of the 21st, appeared to me as a 

 conspicuous and beautiful object. The texture of the tail seemed 

 streaky, as on the 20th, appearing like folds of the most deli- 

 cate gauze. The nucleus and jet of light reminded me of the 

 shape of a shuttlecock, the feathers turned to the right and 

 sloping downwards, and surrounded by a bright glare of lig i ht. 

 Its changed its aspect in a fitful manner, or at least appeared 

 to me to, do so. I do not know that this fitful appearance was 

 VOL. II. — no. in. Q 



