xiv.] FORBES 1 SCIENTIFIC WORK. 469 



principle than the existence of spaces of comparative 

 condensation, including binary or more numerous groups, 

 as well as of regions of great paucity of stars. Thus, 

 to take a familiar instance : No bad representation of 

 stars and their distribution may be made by sparking 

 viscid white paint from a coarse brush upon a dark 

 ground. It is impossible to conceive a nearer approach 

 to a "random scattering." But I am assured by an 

 ingenious friend, who has used this contrivance in aid of 

 pictorial effect, that such an artificial galaxy will present 

 every variety of grouping, with double and treble points 

 innumerable (as I have indeed myself witnessed) ; nor 

 can I well see how, upon any reasonable theory of chance, 

 it should be otherwise. 



' I wish to restrict this letter to the end proposed, that 

 of nakedly setting forth a serious difficulty in an infer- 

 ential interpretation of nature, sanctioned by high and 

 cumulative authority. I shall not therefore attempt 

 now to enquire more minutely into the history of the 

 error, if error it be, nor to insist on the great importance 

 of arguing correctly in cases which admit of so very 

 extensive application. 



' I remain, Gentlemen, 



' Yours faithfully, 



' JAMES D. FORBES.' 



In 1850 he communicated to the British Association a 



paper on the same subject, which was not immediately 



published. Meanwhile, in July 1850, appeared in the 



ftuff/li ftrricw an article by Sir J. Herschel, who 



thus writes to Forbes on the subject : 



' MY DEAR SlR, ' COLLINGWOOD, July 27, 1850. 



'I had hoped to have been able to have sent 

 a copy of an article in the last No. of the Edinburgh 

 10, in \\hirh an objection advanced by you against 



the arguni- nt iV'-m probability of a physical <-<>mi<Ttion 



tin- iii<livilii,Y <lnille >\\\v, drawn fr..ni 



mere juxtaposition, is attempted to be an^wm-il. Hut I 



