Ih^ceedlngs of the Society of Arts. 397 



the Model, by Freebairn, with Bate's Patent Anglyptograph. Presented 

 by Captain Henderson, R. E. (679.) Thanks voted. 



The following Candidates were admitted as Ordinary Mem- 

 bers, viz. : — 



Henry David Hill, Esq. W.S., 2 Picardy Place; William Thomas 

 Thomson, Esq., manager of the Standard Life Assurance Company, 

 2 George Street ; James RoUand, Esq. W. S., 14 Shandwick Place. 



In terms of Law XIII. the Societj- appointed a committee to audit the 

 Treasurer's books, and to report thereon, and generally on the state of 

 the funds of the Society ; the report to be given in at next meeting, viz., 

 on 16th January 1840. The books were laid on the table. 



\bth January 1840.—David Maclagan, M. D., F.R.S.K., 

 Vice-President, in the chair. The following communications 

 were made : — 



1. Description of an Improvement on the Mercurial Registering Thermo- 

 meter of Rutherford, by which the injury frequently caused by the conti- 

 nued contact of the steel index with the mercury is completel}'^ prevented. 

 By Mr John Dunn, optician, 50 Hanover Street, Cur. S.A. The instru- 

 ment was exhibited. (683.) Referred to a committee. 



2. Essay on Life Assurance, No. II., being on the Errors of the Bonus 

 System. By Edward Sang, Esq., actuary, 6 North St David Street, 

 M.S.A. (076.) Tlie objection urged in this paper against the present 

 sj^stcm of bonus is, that it places the interests of different classes of mem- 

 bers in opposition to each other ; and that it enables the present members 

 to declare additions to their own policies, that may have to be paid out 

 of the funds contributed by succeeding members ; and a case was men- 

 tioned in which confessedl}' a draft of this kind to the amount of upwards of 

 L.126,000 was made upon the future members of a Mutual Assurance 

 Society, and was paid by them. The objection was endeavoured to be 

 strengthened by the remark, that, on account of tlie intricacy of the sub- 

 ject, such injustice may be committed without the smallest intention or 

 knowledge of evil. — Essay III. to be read at next meeting. 



0. Verbal Exposition of Daguerreotype. By Andrew Fyfe, M.D., 

 F.R.S.E., M.S.A. (678.) After explaining briefly the mode of con- 

 ducting the process, Dr Fyfe stated the results of experiments in which 

 he had been engaged, with the view of illustrating its rationale. The 

 golden colour given to the silver surface is, in his opinion, not a mere 

 coating of iodine, but an iodid of silver, and when this is subjected to the 

 agency of light in the camera, the affinity between the silver and iodine 

 is weakened on those parts on which the light impinges, and hence the 

 iodine is, as it were, loosened from the silver; consequently, when the 

 plate is exposed to the mercurial vapours, the mercury adheres to those 

 parts only from which the iodine has been detached ; of course where 



VOL. XXIX. NO. I.Vlir. OCTOBER 1840. D d 



