Tribune Frtras Pamphlet Scries. 



11.0">0,000.0()0,000.000 tons: and this earth on 

 v. hii:li \vu llvo. if its whole surface were glowing 

 . tie- -.Hue heat as the sun, would give >-ut in 

 Bverj ->,. ml tli.- Bailie ainoiiiit nf heat that would 

 1 jiveu by burning up 1,000,000.000,000 tons of coal. 

 < 'a inilli-in niilliun t >n.s of coal in every second of 

 tiint -i irlohe only a^ lai !_ r e as our earth ! while the 

 sun, th'- iM'ea 1 eeiiter nf our system, gives out every 

 ,<l an am. unit of ln-.it that would lie Driven out by 

 bunii'ii.' 11, 'i in. " .HMi' i: 1,000,000 of tuns of coal, or ahout 

 ci-_ r !it tiai-s tin- wlmle supply of coal supposed to 

 i in this earth. In every second thesnn jives out 

 l!i w!i >l siipplv ( .f that coal which we look at as 

 iuexli.iM-.ti'-.le, hut which Wi> a TO consuming at such 

 HI a - t mi in ::,'i 1 1 t.r 4,c'i:i years hence there can be 

 I- : ', ; 1 .I ) iiit the coal N.'ill bo exhausted upon the 

 ii ih. 



Tin: sr.v's SPOTS. 



Nn.v. w.- have tn con-idi-r what t ho telescope and 

 other imtru mem- of r.-^-arrh tell us ahout the globe. 

 We have si-i-n its si/e, its mass, what a wonderful 

 nmniint of liL'lit and heat it '.rives; and now we have 

 to ciHiM'h-r what the telescope tells us. J need not 

 P> over i he >,-[-i a of researches by which the aspect 

 of t h -mi ha> ln-en studied ; but I will only remark 

 that if i ;alil:-o and t IP- ut In T.S who studied the sun 

 Jf th:-y had hut known, a-i we know, how much we 

 owe to tin- sun the\ would with a hundred-fold de- 

 gl nf iutei.-st have studied that wonderful orh. 

 A; ihe In-iriniiiiiir of their research they found tho 

 Bun's surface marked from t line to time with large 

 spots, which will now be shown you 



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of 



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whirh I liuuld have 



been very glad to have suspended all tto time 

 for you, but 1 found the size of the screen 

 would not permit me. You will have the diagrams 

 one by one before you, interspersed with lantern 

 views, which by tho kindness of Prof. Morton I can 

 exhibit to you. By the first I will show you the 

 general aspect of the suu, the way the sun appearj 

 with its various spots. That diagram now before 

 you has been taken at tho Cambridge Observatory 

 It ia a photographic picture of the sun. There are 

 four such pictures, and they show you the different 

 appearances of the sun. Sometimes there are a few 

 spots; at others more; at others two zones appear 

 to be strewn with spots. 



It was discovered early that thess spots aro 

 actually attached to the surface of tho sun, that 

 they are carried round, that the sun's globe re- 

 volves in about twenty-live of our days, carrying 

 these spots along with it. Other features were soon 

 recognized in these spots. We will have the second 

 of these diagrams shown, in which you will have a 

 larger picture of these soots, and other pictures will 

 show you what will afterward bo presented on a 

 large scale the appearance of bright spots around 

 the spots called faculu). The spots are not uniform 

 in color, and have an outer fringe, while inside 

 there is a dark pait which the first observers 

 thought was actually black. But no part of the 

 sun's surface, so far as we know, would seem to be 

 actually black. Certain of the bright parts aro 

 strained into white bright streaks, surrounding tho 

 spot, and when the lantern is used you will 

 find clear views of that phenomena will 

 be presented. Wo will next have a picture 

 of the sun's spots presented, and after- 

 ward tho photographic pictures of the spots 

 brought before yon. There is on 3 oth^r pictara 

 which, like tho last, was taican at the Cambridge 

 Observatory, and shows th^ feature.} of these spots. 

 They are well defined. Tho outer outline of the 

 spot is sbaiply defined, and the outliuoof the central 

 spot is well marked, an I then there are white streaks 

 from tho central part towards the surrounding por- 

 tion. All that surrounding portion, especially near 

 the edge of the spot, is, on the sun, brighter than tlu 

 rest of the sun's surface. Now we will have tho 

 room darkened, and these things will bo shown to 

 you by photographs taken by Mr. Rutherfurd. Yon 

 will KCC these various spots, and you will have the 

 assurance that you are not looking at a picture 

 taken by the baud of man, but sun-painted, in which 

 all the features were actually existingon tho surface 

 of the sun at t lie time ; and meantime we will pass 

 on to tho consideration of various features that will 

 have to be presented. 



In this diairrnm you will perceive that the central 

 *rt fc Mftrrounde4 by whitick utreakt, called tb* 



