"runlll"an°!?"ll7a'] PKOCEEDINGS OF SOCIETIES. 53 



the small residuary aberrations which exist in the best object-glasses 

 by an equal and opposite amount of aberrations, as spoken of in the 

 paper ; and in this resj)ect he (the President) thought that the leading 

 opticians would do well to avail themselves of Dr. Pigott's sugges- 

 tions. In addition to this he would mention that the stage itself is 

 one of peculiai* interest, having been made by Dr. Pigott himself, to 

 whose practical skill as a worker on the lathe many could testify. 

 The peculiarity of the stage consisted in the secondary stage being 

 brought up to the primary one, the whole being about a i of an inch 

 in thickness, and even under a ^ the circular motion is so perfectly 

 concentric that the minutest object remains, as it were, fixed on the 

 field of view. There are two screws which regulate the condenser, 

 and also two which regulate the rectangular motion of the stage, that 

 motion being produced by the moving of one circle within another. 

 The abstruse mathematical calculations employed in the correction 

 of the residuary aberration are to be communicated to the Royal 

 Society, and a further communication would be made also to the 

 Royal Microscopical Society. These remarks he (the President) had 

 made in justice to Dr. Pigott. The President added, that Dr. Pigott 

 was precluded from attending the meetings of the Society by the 

 state of his health, but that he was willing to show the Poditra mark- 

 ings at his own residence to any of the Fellows who would favour 

 him with a visit.* 



The list of donations was then read. 



Mr. Slack announced that the Society had received two presents 

 from Dr. Millar : the one, consisting of an original form of the para- 

 bola, devised by Mr. Wenham ; and the other, of the original " finder," 

 devised by the Committee of the Society. Dr. Millar stated that the 

 finder had been obtained from the collection of Mr. Jackson. 



A vote of thanks was then passed to Dr. Millar and the other 

 donors whose names had been mentioned. 



Mr. Slack briefly explained the nature of a communication from 

 Mr. C. Staniland Wake " On Organisms in Mineral Infusions," which 

 will appear in the ' Transactions.' 



Mr. Wake made infusions of coal and other mineral substances, 

 and then examined the organisms which grew from or upon particles 

 they contained. Mr. Wake spoke of these organisms as if they had 

 retained their vitality from the formation of the mineral ; and though 

 this is rather a startling statement, he is not alone in this view, for a 

 similar opinion had been enunciated before the French Academy by 

 M. Bechamp, who had discovered certain bodies in chalk, which he 

 found were capable of acting as ferments, which he named Micro- 

 zymas. He presumed these bodies to have preserved their vitality in 

 the fossil state. 



* Mr. Hogg desires us to insert the following note : — " I regret to find in the 

 report of my observatioas on Dr. Pigott's paper (Dec. 1, p. 333) that the last 

 sentence assumes the form uf a personal comment. Press of engagements un- 

 fortunately prevented me from making an intended and necessary addition and 

 correction, and I now gladly take the opportunity of adding to the above obser- 

 vations of the President my own present opinion of the value of Dr. Pigott's 

 paper." — Jabez Hogg. 



