Nov. 30, 1871J 



NATURE 



83 



anonymous, if we please, but which was referred hy every one 

 who read it to the Astronomer-Royal for Scotland, who showed 

 not the slightest wish to conceal his identity. Doubtless on 

 hearsay evidence (in which, however, he placed, I am sure, as 

 much reliance as I placed in his o\\n statement), Prof. Smyth 

 asserted that Newcomb had anticipated Stone's labours. I took 

 it for granted tliat it was so, since I saw no room or reason for 

 doubt. There was my error. But, says Prof. Newcomb, whence 

 comes the value 8" -87 "w/tic/t it -uill be noted is Mr. Peti-ic's 

 pyramid value ? " and on what does Mr. Proctor found his 

 comments " about my treatment of contacts? I am as much in 

 the dark as ever." I will tell him. The value 8 ''87 has nothing 

 on earth to do (so far as I am concerned) with Mr. Petrie's 

 pyramid value. It is simply the value insisted upon by Prof. 

 Newcomb in a paper which appeared in the Monthly Notices of 

 the Royal Astronomical Society for November 186S ; respecting 

 which Mr. Stone remarked (see the same number of the Notices) 

 that "the point Mr. Newcomb has r.aised is a question of only 

 o"'04, viz. between my value and 8" '87 — a question, therefore, 

 of comparative insignificance." Most just remark ! With my 

 belief as to Prof Newcomb's prior work, was it wonderful that 

 I concluded that 8" '87 was his own pet figure for the parallax? 

 Then it chanced that the Royal Astronomical Society, venturing 

 to ignore Prof. Newcomb's objections, bestowed on Mr. Stone, 

 in 1869, the Gold Medal of the Society for his researches into 

 the Venus transit ; and in the remarks which accompanied the 

 presentation, it was stated that all preceding researches were 

 imperfect in this respect, that (to use my own words) "no fixed 

 rule had been adopted for interpreting the observations of internal 

 contact." Prof. Newcomb cannot fail to see how this statement 

 accounts for the estimate (not my estimate) of his supposed 

 researches. 



As a matter of fact, however^apart from the inference to 

 which Prof Newcomb is so anxious to give point — I am somewhat 

 hardly treated in this matter. When I came to the part of my book 

 where Prof Newcomb's supposed researches should be dealt with, 

 I thought thus in my mind : " Assuredly Newcomb has done 

 this thing, for Prof Smyth says so. Shall I leave his researches 

 unnoticed because I can find no trace of them ? That would be 

 scarcely fair. Moreover, he is an American, and to omit all 

 notice of his work will be so much the more objectionable. 

 Verily I will repeat the statement of my esteemed friend at 

 Edinburgh, and I will combine with it the weighty judgment 

 of my friends at the council-board of the Astronomical Society. 

 Thus will the researches of Newcomb be recorded, and due credit 

 be assigned to him for his industry and skill, while yet no undue 

 weight will be given to the numerical result of his labours. " 



That I thus fell into error I have already admitted. But the 

 error is venial in its nature, and utterly insignificant in its effects. 

 As I am conscious that it aro.se chiefly from my desire (shown in 

 other ways and places) to do justice to our American fellow- 

 workers in science, I am in no way ashamed of it ; and I conceive 

 that Prof Newcomb should have been the last to comment 

 in the manner he has done on the subject. 



I shall not follow him in his discussion respecting irradiation, 

 leaving Mr. Stone to deal, in his own good time, with the 

 arguments by which two Continental astronomers (and one 

 American mathematician) have sought to deprive him of his 

 justly-earned credit. 



1 would submit, in conclusion, that February 1869 (the date 

 of the presentation of the Astronomical Society's medal to Mr. 

 Stone) can scarcely be described as " five years" ago even now, 

 and my treatise on the sun was published in February 1871, 

 Chapter I. being in type in November 1870. Nor has the council 

 of the Astronomical Society (or any member of it) expressed any 

 doubt, as yet, regarding the justice of the decision arrived at in 

 1869. Yet not a few members of the council have paid marked 

 attention to Prof. Newcomb's attacks upon Mr. Stone. Vei-bum 

 sat. Rich. A. Proctor 



Brighton, Nov. 24 



The Density and Depth of the Solar Atmosphere 



The demonstration relating to the density and depth of the 

 solar atmosphere, published in Nature Octobers, 1871, page 

 449, has been entirely misconceived by Mr. Hall. The volume 

 of the terrestrial atmosphere is an element which obviously has 

 nothing to do with the question. Atmospheric air, if raised to a 

 temperature of 3,272,000' Fah., will expand 6,643 times ; hence 

 a vertical column forty-two miles high will reach a height of 



279.006 miles, if brought to the stated temperature. The basis 

 of computation adopted by Captain Ericsson being an area of one 

 square inch, he shows that a medium similar to the terrestrial 

 atmosphere containing an equal quantity i.f matter for corre- 

 sponding area, transferred to the solar surface, will, owing to the 

 superior attraction of the sun's mass, exert a pressure of 147 x 

 27 9 = 410 pounds. And that, if the said medium be heated to 

 a mean temperature of 3, 272,000° Fah., it will expand toaheightof 



Jsi^ = 10,000 miles above the solar surface. But, if a gas 



27-9 

 composed chiefly of hydrogen I '4 times heavier than hydrogen 

 the specific gravity of which is iV of that of air, be substituted, 



the height will be — ! = 100,000 miles. Admitting 



I '4 

 that the ascertained coefficient of expansion, 0'00203 for 1° Fah., 

 holds good at the high temperature before referred to, the stated 

 altitudes of the solar atmosphere cannot be dispu'ed. Mr. Ball's 

 announcement concerning the properties of spheres, it is scarcely 

 necessary to observe, has no bearing on the foregoing calculations. 

 With reference to the effect of inten-e heat, it mil be well to 

 bear in mind that the before-mentioned rate of expansion holds 

 good for atmospheric air — within an insignificant fraction — under 

 extreme rarefaction as well as under high temperatures. We 

 have no valid reason, therefore, to suppose that any deviation 

 from the ascertained law of expansion takes place in the solar 

 atmosphere, sufficient to alter materially the before-mentioned 

 computations of its depth. 



Mr. Ball, in expressing the opinion that we shall not gain much 

 correct knowledge of the snlar atmosphere by the inquiry insti- 

 tuted by Captain Ericsson, forgets that the retardation which the 

 radiant heat suffers in passing through our atmosphere h-is been 

 ascertained, and tfiat the properties of atmospheric air with 

 reference to temperature and expansion are nearly identical with 

 those of hydrogen, now admitted to be the chief constituent of 

 the solar atmosphere. It is evident that Mr. Bill does not com- 

 prehend the object of adopting the terrestrial atmosphere as a 

 means of determining the extent and dep^h of the solar atmo- 

 sphere, since he does not perceive that the comparison instituted 

 by Captain Ericsson has brought out the fact that either the depth 

 of the sun's atmosphere exceeds 100,000 miles, or it contains less 

 gaseous matter than the earth's atmosphere for equal area. The 

 importance of this conclusion with regard to the determination of 

 the retardation of the radiant heat in passing through the sun's 

 atmosphere is self-evident to all who regard solar radiation as 

 energy which cannot be absorbed unless an adequate amount of 

 matter be present Mr. Ball's suggestion that the retardation 

 depends on the "chemical, i.e. molecular-constitution" of the 

 solar atmosphere, calls to mind how i^libly some physicists talk 

 of "arresting" one half, or more, of the solar energy. These 

 reasontrs apparently do not perceive that the means of arresting 

 such stupendous energy is more difficult to conceive than the 

 means of producing it. 



Respecting the experiments which have been made with incan- 

 descent cast-iron spheres, and inclined discs, it is important to 

 mention that previous experiments had established the fact that 

 the radiant heat of flames transmits equal temperature, under 

 similar conditions, as incandescent cast iron. The inference, 

 therefore, which has been drawn by Captain Ericsson from the 

 results of his experiments with incandescent cast-iron spheres 

 regarding the feebleness of radiant heat emaiiating from the sun's 

 border is not unwarrantable as supposed by Mr. Ball. 



New York, Nov. 10 Thule 



An Aberrant Foraminifer 



I CH.ANCED upon an aberrant form of 

 Peneroplis the other day, in which the Iree 

 terminal series of chambers of this Forami- 

 nifer, ordinarily single, is constricted into 

 two distinct tubes. 



Though new to me, it may not be sj 

 to some of your readers ; Dr. Carpenter, 

 however, does not mention it in his mono- 

 graph. 



St. John's College, Cambridge W. Johnson Sollas 



"New Original Observation" 

 Ernst Fribdixokr, of Vienna, begins a communication on 

 the subject of "which cells in the gastric glands secrete the 



