ASTRONOMY. 159 



During 1888 spots were few, small and in low latitudes, aud there 

 were frequent intervals in which no spots at all were seen, longer inter- 

 vals in fact than any since the minimum of 1879. The most prolific 

 mouth as to entire spotted area, though not as to number of spots, was 

 November, following immediately a long period of quiescence. There 

 was a rough tendency of spots to certain solar longitudes and in lati- 

 tude, they continued to be more numerous in the southern than in the 

 northern hemisphere. Facula^ did not vary simultaneously with spots, 

 but their diminution as compared with 188G and 1887, was slight. They 

 showed a very noticeable development during the secondary maximum 

 of Sejitember, while the prominences fell off considerably both in Sep- 

 tember and November, but attained their greatest development in 

 March and April. 



Solar spectrum. — Experiments made by Professor Trowbridge and 

 Mr. C. 0. Hutchins at the Jefferson Physical Laboratory in Cambridge, 

 have overthrown tlie proof brought forward in 1879 by Dr. Henry Dra- 

 per of the existence of oxygen in the sun. They show that when suf- 

 ficiently powerful apparatus is used to bring out minute details of the 

 spectrum of oxygen and of the sun, the bright regions of the solar spec- 

 trum disappear, and hence also the apparent coincidences between tliem 

 and the spectrum of oxygen uijon which Dr. Draper based his proof. 

 The bright bands obtained by Dr. Draper are in fact occupied by num- 

 erous dark lines of variable intensity. 



Continuing their experiments however they have been led to con- 

 clude that there is unmistakable evidence of the existence of carbon in 

 the sun. 



In a valuable paper by Mr. C. C. Hutchins and Mr. E. L. Holden, 

 evidence is brought forward to show the i)robable existehce in the sun 

 of bismuth, silver, and platinum, while tin potassium, and lithium are 

 more doubtful. For cadmium two perfect coincidences were found, 

 while there was no good evidence in favor of the presence of lead 

 cerium, molybdenum, uranium or vanadium. 



Prof. S. P. Langley has published in the American Journal of Science 

 an abstract of a memoir on the invisible solar and lunar spectrum, in 

 which he summarizes the result of investigations carried on at the Al- 

 legheny Observatory in continuation of his previous researches on the 

 infra- red of the solar spectrum to the extent ot about three microns. 

 By means of the improved apparatus described, the extreme infra-red 

 solar si^ectrum has now been searched from three to over eighteen mic- 

 rons; and it is shown that in this region the ratios between solar and 

 lunar heat are comi)letcly changed from what they are in the visible 

 si)ectrum. While the solar light in the latter is about five hundred 

 thousand times that of moonlight, the solar heat received in the invisi- 

 ble part of the spectrum is ])robably less than five hundred time^ the 

 lunar. These studies also promise important results for meteorology, 

 by opening to observation the hitherto unknown region of the spectrum, 



