51 
The substitution of a filament of carbon for platinum has 
now placed the incandescent electric light in the rank of 
recognised illuminants, and when not raised to too high a 
temperature the carbon filament is very durable. When, 
however, a high degree of incandescence is attained, an 
atmosphere of carbon vapour is formed in the interior of the 
bulb which condenses on the glass and forms a dark lustrous 
surface which obstructs the light in the same manner as 
when a filament of platinum was employed. 
The behaviour of the carbon and the platinum in each of 
these lamps clearly shows that the most dense and refractory 
substances in nature vaporise at high temperatures while 
still retaining their solid form. 
Electric lamps were exhibited by Mr. Wilde showing the 
condensed platinum and carbon on the interior surfaces of 
the glass bulbs. 
“ Remarks on Professor Osborne Reynolds’ paper ‘ On 
Isochronous Vibrations,’ ” by Robert Rawson, Esq., Hon. 
Member, Assoc. I.N.A., Mem. of the London Mathematical 
Society. 
At the ordinary meeting, Nov. 28th, 1882, Professor 
Osborne Reynolds, M.A., F.R.S., read an interesting paper 
entitled “On an Elementary Solution of the Dynamical 
Problem of Isochronous Vibrations.” It would seem that 
the object of this paper is intended to supply a remedy for 
what the author conceives to be a serious defect in our 
existing elementary works on Dynamics. 
Experience, it appears, has shown Professor Osborne 
Reynolds that the obscurity in which the principles of 
Dynamics are enveloped by means of the language and 
symbols of Differential equations, “ stands very much in the 
way of those who are commencing the study of practical 
mechanics.” 
I am not able, from my own experience, to share the views 
