64 



ASTKONOMICAL PHENOMENA AND PEOGEESS. 



in the extent of the light spot or whitish cloud, 

 which marks the crater, he says he has ob- 

 served phenomena of tbe same kind on the Mare 

 Crisium ; and about seventy sets of measures 

 of Dionysius yield the same result, though not 

 to so great an extent as in the case of Linne". 

 Mr. Huggins has published a view of Linn<5 as 

 seen by him May 11. It represents an oval 

 white spot and to the west of its centre a white 

 ring surrounding a black spot. He remarks that 

 at the time the diagram was made tbe shallow 

 saucer-like form of Linne" was not seen, but he 

 had detected it on other occasions. July 9th, 

 he made other observations with a power of 

 500, and gives the following measurements : 



Length of the bright spot 7".85 



Breadth G".H 



Diameter of small crater I".?! 



In Comptes Rcndus, June 17, 1867, appears a 

 paper by "Wolf on this interesting subject. He 

 says that since the 10th of May he had noticed 

 that the crater Linng continued to exist, but 

 with a much smaller diameter than that indicat- 

 ed in the maps of Lohrmann, Beer, or Madler. 

 In the centre of the white spot could be seen a 

 circular black hole, bordered on the west by a 

 portion of ground which seemed raised above 

 the remainder of the spot. This circular black 

 hole, "Wolf regards as a deep crater deeper 

 than most of the craters that surround it, judg- 

 ing from the comparative intensity of the 

 shadows. He thinks that the lustre of Linne" 

 has not changed its total diameter reinaining 

 about the same but that a comparison of maps 

 indicates a real alteration, for some of those 

 maps figure a large crater occupying all the 

 space now filled by the white spot. Wolf 

 employed magnifying powers of 235, 380, and 

 620. In De la Eue's large photograph of the 

 moon (1858), Bessel and Sulpicius Gallus ex- 

 hibit indications of an interior shadow, while 

 Linn6 figures as a white spot ; and the same 

 is seen, though clearer, in the great photo- 

 graph obtained by Mr. Eutherfurd, of New 

 York, March 4, 1865. Therefore, "Wolf con- 

 cludes that, "apart from the indications sup- 

 plied by the maps of Lohrmann, Beer, and 

 Madler. to which may be opposed the counter- 

 indications of Lahire and Schroter, we only 

 possess a single positive document testifying 

 that Linne" has undergone any change, and that 

 is. the affirmation of Schmidt that his crater 

 and drawings of 1841 represent the object 

 differently to wliat it is now seen." 



Father Secchi sent to the French Academy, 

 from Eome, February 14, 1867, a letter in which 

 he says, that, on the 10th of that month, be- 

 tween 9 and 10 p. M., the crater Linne" entered 

 into the sun's light, and close by the limiting 

 circle a small prominent point was seen with a 

 little shadow, and round this point an irregular 

 circular corona very flattened. The -weakness 

 of the light and the proximity of the moon to 

 the horizon did not allow the observations to 

 be prolonged. On the llth, in the evening, 

 Linne" had already advanced into the light, and, 



at seven o'clock, a very small crater was dis- 

 tinctly seen surrounded by a brilliant white 

 aureole, which glittered against the dark ground 

 of M. Serenitatis. The size of the orifice of 

 the crater was at most ^ of a second, and the 

 aureole was a little larger than Sulpicius Gal- 

 lus. Father Secchi does not doubt that a change 

 has taken place in Linne 1 , and thinks it probable 

 that an eruption has filled the ancient crater 

 with a material white enough to look bright 

 against the dark ground before mentioned. 



New Map of the Moon. The Lunar Com- 

 mittee of the British Association published 

 during the year two sections of their map on a 

 scale of 220 inches to the moon's diameter, 

 comprehending two areas of 27 superficial de- 

 grees, which are equal to 17,688 square miles 

 English in the two. On these sections, printed 

 red, the planets, craters, mountains, valleys, 

 and other objects are laid down in outline; 

 each known object being distinguished by a 

 reference number to the text which accompanies 

 the two sections. The portion of the moon em- 

 braced by the sections extends 6 degrees west- 

 erly from the first meridian and 10 degrees 

 southwardly from the equator. Photographs 

 taken by M. De la Eue and by Mr. Eutherfurd 

 (New York) have contributed very materially to 

 the determination of outlines and the insertion 

 of small objects not discernible under the high 

 illumination of the moon. Several of the smaller 

 objects have been inserted from telescopic ob- 

 servations. The whole of the work has been 

 executed independently of the labors of previous 

 selenographers, with the exception of points of 

 the first order ond a few special instances. It is 

 especially stated in the text that the map is not 

 intended to be perfect or complete, but merely 

 a guide to observers in obtaining data for con- 

 structing a complete map of the moon. For 

 this purpose numerous observations are essen- 

 tial, and with a view to accomplish it, the areas 

 are divided into zones of 2 degrees of latitude 

 each, which are so allotted that every zone of 

 1 degree may be examined by two independent 

 observers, the ground of each overlapping and 

 dovetailing into that of the other. The intention 

 of this examination is to endeavor to fix, by the 

 aid of two independent observers, the exact 

 state of a designated lunar object at a given 

 epoch; for, if from the observations in a given 

 zone, the characters and appearances of the 

 object in that zone can be settled beyond dis- 

 pute, from the testimony of two witnesses and 

 authoritatively published by such a body as 

 the Lunar Committee, it follows that the record 

 so published can be referred to at any future 

 time and the question of fixity or change of 

 any of the objects during the interval definitely 

 settled. The Committee recommend that each 

 object be examined by the observers when the 

 objects are near the morning and evening ter- 

 minators, and also on the days succeeding and 

 preceding the passage of the terminators over 

 the areas' through a period corresponding to 

 at least three lunations and that a record be 



