362 



SCIENCE. 



[Vol. VI., No. 142. 



articulation, upon which subject Mr. Bell has be- 

 stowed a vast deal of time and study. But a lim- 

 ited number of teachers in training can be accom- 

 modated, and the opportunity is doubtless one which 

 will be eagerly sought. 



The national museum, Mr. Barnum, and the big 

 elephant Jumbo, have all received a good deal of 

 public notice arising from the singular death of the 

 gigantic and lamented beast. The pubhc was at 

 first assured that the bones of this creature, fated to 

 disturb two continents, were to rest in the national 

 depository, although it was stated that the stuffed 

 skin was to adorn the collection of a New England 

 college. Recent information, however, seems to 

 indicate that Mr. Barnum has awakened to the fact 

 that he now has two Jumbos, instead of one, and 

 that both may continue to be sources of profit for 

 some time to come as parts of one or two travelling 

 ' aggregations. ' There is little doubt but that a year 

 or two of this sort of an existence would gTeatly 

 diminish the value of the skeleton of the elephant, 

 and it is stated that the director of the national 

 museum is in coiTespondence with Mr. Barnum 

 with a view to prevent such a calamity, in which 

 effort everybody wishes him success. Reference 

 was made in the letter of two weeks ago to the 

 large acquisitions of the museum tlu-ough the 

 New Orleans exposition. The curators of the 

 various departments are getting some of these col- 

 lections into shape, and although they are in some 

 instances embarrassed by lack of space, some effec- 

 tive displays will be made. A very valuable, and, 

 in some respects, ty^ncal collection was presented 

 by the Japanese government, and has just been un- 

 packed. It is intended to present an epitome 

 of the arts and industries of the country, and as 

 such it will doubtless be kept together for some 

 time, and conspicuously displayed. It includes 

 illustrations of the handicraft of the ingenious 

 natives of Japan in pottery, porcelain, lacquer, 

 bronze, silver, and copper, and also models and 

 water-color sketches illustrating Japanese fisheries, 

 domestic occupations and the like. Z. 



Washington, D. C, Oct. 19. 



LETTERS TO THE EDITOR. 



♦»♦ Correspondents are requested to be as brief as possible. The 

 writer's name is in all cases required as proof of good faith. 



An attempt to photograph the corona. 



Mr. W. H. Pickering having courteously sent me a 

 copy of Science (August 14), containing an article 

 entitled ' An attempt to photograph the solar corona 

 without an eclipse.' may I ask you to insert the few 

 hues which follow in the next number of your 

 journal ? 



Passing by all those points which are covered, 

 directly or indirectly, by my reply to Mr Pickering's 

 first letter {Science, April 3), I find only two matters 

 which I consider it necessary to notice. 



1. Mr. Pickering says : " The inferiority of the best 

 gelatine plates to the human eye in this respect 

 [small differences of light] is very readily shown by 

 an attempt to photograph distant mountains." He 

 then goes on to say : " Another illustration of the 

 same thing is the impossibility of photographing the 

 moon in the daytime, when the sun is high above 

 the horizon. Although the moon may be perfectly 

 distinct to the eye, the negative shows no trace of it." 



To your scientific readers, the reasons will readily 

 suggest themselves, why, in the case of the moon in 

 the daytime at some angular distance from the sun, 

 the eye has an advantage over the plate, while, in the 

 case of the corona, the plate has a great advantage 

 over the eye. Apart from any such considerations, 

 as a matter of fact, there is no difficulty in photo- 

 graphing the moon at noonday. Yesterday I took, 

 with the apparatus used on the corona, four nega- 

 tives on bromide plates (Edward's), between 11 30 

 A.M. and noon, in full sunshine. On all the plates, the 

 moon is very distinct and v^ ell defined. The moon at 

 noonday, unless too near the sun, is an easier object 

 to photograph than the corona. It is obvious, there- 

 fore, that photographic methods, which are not deli- 

 cate enough for the moon, must utterly fail if applied 

 to an object still more difficult, as the corona un- 

 doubtedly is at ordinary elevations. 



If Mr. Pickering's statement of the ' impossibihty ' 

 of photographing the moon under the conditions 

 already named, rests upon his own experiments, some 

 light may come upon a point which has occasioned 

 me surprise, namely, that Mr. Pickering does not 

 appear to get upon his plates the defects of his own 

 apparatus ; for example, those of the position of his 

 shutter and those of his spectacle lens. In some ex- 

 periments I made with a shutter similarly placed, 

 very strong diffraction effects appeared on the plates, 

 effects stronger than any photographic action which 

 could be supposed to be due to the corona. 



2. With regard to Mr. Pickering's experiments, I 

 would point out that the conclusion to which they 

 lead him, namely, " It therefore seems that even in 

 the clearest weather the reflected light of the atmos- 

 phere is 300 times too strong to obtain the faintest 

 visible image of the true coronal rays," appears to 

 me to be irreconcilable with the direct observations 

 of Professor Langley and others of the planets Mer- 

 cury and Venus, as black disks before they reach the 

 sun. Professor Young says : " Of course this implies 

 behind the planet a background (of corona) of sen- 

 sible brightness in comparison with the illumination 

 of our atmosphere." (The sun, p. 229.) 



The Bakerian lecture read recently before the 

 Royal society, in which I have discussed some of 

 these points more fully, will be in print in a few 

 weeks. The photographic method is now being tried 

 at the Cape of Good Hope, under the scientific condi- 

 tions I have pointed out as essential, by Mr. Ray 

 Woods, under the able superintendence of Dr. Gill, 

 F.R.S. William Huggins. 



From the above interesting communication by Dr. 

 Huggins I regret to find that he has failed to see my 

 reply, published in Science, for April 29, to his letter 

 of April 13. My experiments on the position of the 

 drop-shutter were there taken up with some detail. 

 Also other points presumably referred to in the be- 

 ginning of his article are discussed. 



As to the observations of the planets Mercury and 

 Venus, as black disks before they reach the sun ; the 



