22 REPORT — 1861. 



2. Large globes are formed by rotation, consisting of cold cosmic dust, similar in' 

 Bbape, but not in matter, to those supposed by La Place's theory, which are red-hot 

 lic[uids. 



3. Consolidation begios from the outermost stratum near the surface. Pressm-e 

 within elicits electric and chemical action : heat is disengaged : new compounds are 

 formed, gaseous, liquid and solid. 



4. A hollow shell of solid matter is generated, containiag withia it matter stiU 

 in progress of consolidation, as exhibited to some extent by septaria. 



6. The difference of tension within and without the shell causes a real explosion, 

 by which fragments are dispersed in cosmic or interplanetary space to traverse it 

 in all directions. 



II. Tlie arrival of Meteorites iqwn our Earth. 



1. A fragment in its course comes into contact with oiu" globe. 



2. The fragment is arrested by the resistance of the atmospheric air. It may in 

 many cases pounce directly upon the earth. 



3. Pressiu'e on its passage through the atmosphere elicits light and heat, rotation 

 ensues, and a melted crust is formed. 



4. The white-hot compressed air is spread out in the form of a fireball, closed up 

 behind, the fragment enclosiag a vacuimi space. 



5. The cosmic course is at an end when the fragment has been ai-rested by the 

 ah". 



6. Light and heat are no longer generated : the ball will collapse with a loud 

 report, or several following each other. 



7. The cosmic cold within the aerolite assists in reducing the heat of the melted 

 crust. 



8. The meteorite falls down upon the eai-th like any other ponderous body, the 

 hotter the better conducting material it consists of. 



On the Quantity of the Acceleration of the Moon's Mean Motion, as indicated hy 

 the Records of certain Ancient Eclipses. By the Eev. Edward Hincks, D.D. 



The question which the author proposed to discuss was whether the acceleration 

 of the moon's mean motion relatively to the sun and stars was 12 or 13 seconds, 

 multiplied by the square of the number of centm'ies from 1800, or only about two- 

 thirds of that magnitude. The quantity assumed by M. Hansen in his lunar tables 

 is 12" '18 ; and the Asti-onomer Royal has given his opinion that this is somewhat 

 too small. The question is not to be decided by theory. Professor Adams has 

 shown that the quantity which would be produced by gi-avity is far less than this, 

 and less than is certainly indicated by observation ; and that, consequently, some 

 other cause than gravity must have been in operation. Theory cannot determine 

 what is due to this unknown cause ; and therefore the quantity of the acceleration 

 can be determined by observiition alone. 



The observations on which the Astronomer Royal relied were solar eclipses, of 

 which he believed that there were four, of which there were such authentic records 

 as to determine with tolerable accuracy the quantity of the acceleration. He 

 rejected the records of lunar eclipses, on accoimt of the want of precision which 

 there must be in the obsei-vations. In the present paper the author eudeavoiu-ed 

 to show that the four alleged eclipses of the sun, on which the Astronomer Royal 

 relied, furnished no sufficient data for determining the acceleration ; and that, on 

 the other hand, there were at least two of the lunar eclipses recorded by Ptolemy 

 which afforded means of determining the quantity of the acceleration with tolerable 

 accuracy, and which, if the author's calcidations were con-ect, proved that it did 

 not much exceed 9". 



The four eclipses of the sim on which the Astronomer Royal relied were that of 

 Agathocles ( — 309, Aug. 14), as to the date of which there is no question, nor as to 

 its totality where the fleet was ; the latitude in which the fleet was, is however, 

 within certain limits, an indeterminate quantity, as is the hour when the eclipse 

 began. WTiile therefore this eclipse affords conclusive evidence of the fact that 

 the moon's motion formerly was less than it is now, it proves nothing as to the 

 question now discussed, whether the acceleration was about 9" or between 12" and 

 13". It is admitted that the former supposition would satisfy the requirements o 



