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(Entered at the Post-Offlce o£ New York, N.V., as Second-Class Matter.J 



A WEEKLY NEWSPAPER OF ALL THE ARTS AND SCIENCES. 



Eighth Year. 

 Vol. XVI. No. 3i 



NEW YORK, July 118,1 1890. 



Single Copies, Ten Cents. 

 $3.50 Per Year, in Advance. 



SUN-SPOTS AND PREDICTIONS. 



Attempts are continually being- made to conQect terres- 

 trial weatber and storms witb the motions and positions of 

 tbe moon, the planets, and the sun. It has been fairly well 

 shown that at the time of full moon there is a tendency, in 

 some parts of the world, toward a diminution of clouds. One 

 computation has shown a slightly greater rainfall during new 

 moon on the Atlantic coast, but precisely the contrary on the 

 Pacific coast. There has also been a very slight evidence of tbe 

 increase of thunder-storms at tbe new moon. The influence 

 of tbe planets must be absolutely inappreciable. When we 

 consider the sun, however, we see at once the intimate con- 

 nection between his radiant energy and all activities upon 

 the earth. Tbe growth and well-being of every living thing 

 are absolutely dependent upon the sun's light and heat. It is 

 believed by many that the sun's heat is the only agent to be 

 considered in seeking for an explanation of our storms and 

 all our weather changes. It is undoubtedly true that some 

 form of solar energy is concerned in our storms, but it would 

 be quite hazardous to say that electric influences from the 

 sun are not far more potent for producing storms than even 

 its beat. As the sun's heat is the most prominent energy 

 recognized by our senses, every attempt has been put forth 

 to determine whether this is constant as regards our climate, 

 or whether there are fluctuations at long intervals. It is 

 plain that these changes, if they exist, cannot be appreciable 

 to our thermometers for centuries. The difficulty of meas- 

 uring the intensity of solar rays by direct observation has 

 been practically insuperable; and we may say that the total 

 amount of heat which we receive is so great, as compared 

 with its fluctuation from the greatest to tbe least, that we 

 cannot hope for any definite solution of that question for 

 years to come. 



Coincidences. 



In seeking any relation .between the sun's light, heat, ro- 

 tation, or appearances, and terrestrial phenomena, it is un- 

 safe to trust to mere coincidences; but some connection of 

 cause and eff'ect should be established. For example: on 

 Aug. 3, 1872, while Professor C. A. Young was examining 

 the solar prominences witb a telescope, he saw a most vio- 

 lent outburst upon the sun, and noted the exact instant 

 when it occurred. Afterwards he found that his assistant 

 at that very moment had observed a violent agitation of his 

 magnetic needle; and an examination of the records at Kew, 

 England, revealed exactly the same disturbance of the nee- 

 dle there. This may safely be regarded as more than a mere 

 coincidence, and proves, in connection with other observa- 



tions of a like nature, the intimate relation between solar 

 disturbance and terrestrial magnetism. 



It is well known Ihat the sun is periodically spotted; that 

 is, once in about eleven years spots gradually appear, and 

 increase near tbe sun's equator. A remarkable fact about 

 these spots is that their motion very near the sun's equator 

 appears to be faster than in higher latitudes They revolve 

 or come in sight in a little over twenty-five days in the for- 

 mer position, and in about twenty-seven days in the latter. 

 This single fact should lead a great many of those who be- 

 lieve that our tornadoes are produced just as the spots ap- 

 pear by rotation, or about twenty-six days apart, to doubt 

 the sufficiency of the explanation, because any such peri- 

 odicity would be entirely broken up from the variable rota- 

 tion period of the spots. The cause of these spots has not 

 been well established, but it is probable that they are the 

 result of increased electric activity on tbe sun. Tbe attempt 

 to connect this eleven-year period with our weather has 

 proved intensely fascinating, and volumes of researches have 

 been published. Such comparisons hav3 proved, in the 

 main, very illusory. While an apparent connection would 

 be found in a few periods, yet, as the number of observations 

 increased, the supposed connection was disproved. A single 

 illustration will suffice. The attempt has been made repeat- 

 edly to connect the sun-spot period with fluctuations in tem- 

 perature. In the nature of the case, it is impossible, per- 

 haps, to prove whether the spots show the sun to be hotter 

 or cooler during their existence. The fluctuations of tem- 

 perature on the earth certainly do not show a preponderance 

 either way, when compared with the appearance of sun- 

 spots. This does not necessarily prove, however, that the 

 spots do not influence our temperature, or that they do not 

 show increased heat in the sun ; for this increased heat would 

 tend to produce clouds from a greater evaporation, and these 

 in turn would prevent the sun's rays reaching the earth, and 

 this would result in a cooling rather than a heating, which 

 would mask the spot influence (see Monthly Weather Re- 

 vieiv, January, 1888). 



Auroras. 



Research has shown conclusively that our auroras and 

 magnetic storms have an eleven-year period, and this is co- 

 incident with spot fluctuations; that is, as activity in spots 

 increases, our auroras increase, and vice versa. It has also 

 been definitely settled that the aurora is an electric phenom- 

 enon, and is intimately connected with magnetic storms on 

 the earth. Here we have practically a number of coinci- 

 dences which may be said to prove a definite connection be- 

 tween these phenomena without a positive knowledge that 



