21 
has not been properly corrected for chromatic aberration, lines are 
seen with coloured fringes, blue if the lens is ‘‘ under-corrected,”’ 
and reddish if ‘‘over-corrected.”” These aberrations had been 
_ removed by combining two glasses containing opposite properties, 
_ and this was the secret of the manufacture of achromatic glasses. 
Mr. Suffolk then explained three methods of varying the magnifying 
_ power—tIst, by using a more powerful object glass ; 2nd, by using 
a deeper eye piece ; and 3rd, by elongating the body of the micro- 
_ scope. There are two kinds of eye-pieces, namely, the Huyghenian, 
invented by a Dutch astronomer, consisting of two plano-convex 
glasses, the flat surfaces of which are directed upwards, the one 
_ nearest the eye of the observer being the ‘‘ eye-glass,’’ and the one 
_ at the greater distance the ‘‘ field-glass.”” The other eye-piece is 
_ that invented by Ramsden, and is called the ‘ positive ” eye-piece, 
_ which only shows an object well in the centre, and is used in transit 
_ telescopes, theodolites, &e. It differs from the Huyghenian eye- 
piece, inasmuch as, by it an object may be viewed beyond itself. 
_ Referring to microscope stands, Mr. Suffolk strongly recommended 
_ that invented by Wenham, and then passed on to consider the 
- action of binocular prisms, and the arrangements which had been 
_ perfected by Mr. Wenham, which that gentleman had-considerately 
given to the public, instead of realising a large fortune, as he might 
have done by patenting his valuable invention. 
%y At the termination of the lecture, the President accorded, in 
_ the name of the Club, a cordial vote of thanks to Mr. Suffolk for 
_ the valuable instruction he had imparted. 
‘The following members exhibited their microscopes, viz :— 
TT. R. Adams, M.D., P. Crowley, J. 8. Johnson, H. Long, G. 
Manners, G. Perry, and J. G. Price. It was stated during the 
evening that Mr. Mc Kean had consented to undertake the duties 
_ of Hon. Secretary in place of Mr. Henry Long. 
il 15th, 1874.—Henry Lez, Esq., President in the chair. The 
ninutes of the previous meeting having been read and confirmed, 
: Mr. Edward Mallett, Mr. John H. Ley, and Mr. John H. Baldock. 
The following were proposed for membership :—Mr. George Curling 
nd Mr. Jesse Curling. 
Mr. D. E. Gopparp gaye a lecture on the ‘‘ Spectro-micro- 
scope,” and illustrated his subject with numerous diagrams. At 
its conclusion, a hearty vote of thanks was passed to him. The fol- 
lowing members exhibited their microscopes :-—Messrs. J. Gregory, 
J. 8%. Johnson, EK. Lovett, G. Manners, J. G. Price, A. D. Taylor, 
