202 Association of Geologists and J\aturalists. [Nov., 



8. The homologous parts of molecules shnilarly and simulta- 

 neously undergo this variation as regards the attraction. 



9. The parts of a molecule on opposite sides of a pole, have a 

 different amount of variation of attraction. 



10. If the state of the attraction which produces a primary 

 cube or prism, is considered its normal state, when secondary 

 planes are produced, there is a decrease of force in the direction 

 of the principal axes, and in a simple ratio. 



11. The diminution of attracting force in the primary axes, on 

 which the formation of a secondary depends, consists partial ac- 

 tion of their force along intermediate axes, symmetrically situated 

 with reference to the primary axes; and the greater or less amount 

 of diminution determines the kind of distribution. 



12. The direction of cleavage may indicate in any species of 

 matter which set of axes is dominant, or strongest in attracting 

 force, the primary or a secondary set. 



13. Those variations of attraction, producing secondary forms, 

 depend often on surrounding bodies, favoring the concentration or 

 diffusion of the attracting force; and the causes often act simul- 

 taneously in nature over wide areas. 



14. In an enlarging crystal, one axis (or two,) may have the 

 action of attraction accelerated by extrinsic influence, and this 

 acceleration or retardation affects equally all crystals forming to- 

 gether under the common circumstances. 



15. The action of cohesive attraction is often intermittent, pro- 

 ducing seriate results, as exemplified in the cleavage of crystals; 

 and the specific rate of intermittent action is different for unequal 

 axes. 



A specimen of clay stone was exhibited in confirmation of these 

 views, taken from Sharon, Vermont, (nine miles west of the Con- 

 necticut;) it occurs in successive deposits at least one hundred 

 and twenty feet deep. 



A letter from Mr. Bond was read, stating that the great nebula 

 of Orion, which had been hitherto unresolved, was resolved, by 

 the Cambridge instrument, into innumerable bright points of 

 light. 



CAMBRn)GE Obskrvatory, Sept. 22, 1847. 

 Dear Sir — You will rejoice with me, that the great nebula of 

 Orion has yielded to the powers of our incomparable telescope. 

 This morning, the atmosphere being in a favorable condition at 

 about 3 o'clock, the telescope was set upon the Trapezium in the 

 great nebula of Orion. Under a power of 200, the fifth star was 

 immediately conspicuous; but our attention was directly absorbed 

 with the splendid revelations made in its immediate neighbor- 

 hood. This part of the nebula was resolved into bright points of 



