27 
Mr. W. L. Carpenter exhibited his modification of Mr, Sorby's 
original form of Micro-spectroscope, in which the prism and achromatic 
condenser were underneath the microscope-stage, and the slit on a detached 
stand. He explained and illustrated the method of using it, and pointed 
out that in this form of instrument, by varying the relative focal lengths 
of the object-glass and the condenser, the spectrum could be made of any 
required size in the field of the microscope ; but that, on account of the 
great number of separate moveable parts, the satisfactory manipulation of 
the whole was very difficult. The spectra of cochineal, blood, cudbear, 
&c, were shown, and also the mode of using the instrument in actual 
investigations. 
Dr. W. B. Herapath related his experience with Mr. Carpenter's 
instrument, which he had employed in a Toxicological enquiry, and describ- 
ed the Eye-piece Spectroscope for adaptation to the microscope, as now 
manufactured by Mr. Browning. The use of this involved scarcely any 
more trouble than the use of an analyzing polariscope prism, but there was 
no means of varying the size of the spectrum, and, until very lately, it 
was much more difficult to compare two spectra simultaneously, than it 
was in the first described instrument. The speaker described minutely the 
course of investigation pursued by him with reference to the supposed 
bloodstains on the hatchet used in the Aberdare murder. Dr. Herapath 
also showed a number of preparations which he had made in the course of 
an enquiry into a supposed poisoning case at Malmesbury, where it had 
been thought that the death of the deceased had been caused by bichloride 
of mercury. He had obtained mercury from the viscera, &c, sent to him 
for examination, but in no case was it in the soluble form, but almost 
entirely in the metallic state, or as sulphuret, and as he was not aware of 
any reducing agent in the body sufficiently powerful to bring mercury to 
the metallic state from its chloride, he concluded that the mercury found, 
resulted from the absorption of medicinal preparations of mercury, 
administered in a perfectly ligitimate manner. 
The President showed a number of photographs which, when mounted 
with starch, became covered with yellow spots, and asked the members 
present their opinion upon the cause of them, and the possible means of 
preventing them from occurring. 
ZOOLOGICAL SECTION. 
Thursday, April 12. — Dr. Henry Fripp, President of the Section 
in the chair. 
Mr. C. O. Groom-Napier exhibited an interesting series of bones of 
the Dodo, chiefly leg-bones, and read an extract from the Mauritius 
Commercial Gazette, quoted in the Zoologist for February, 1866, with 
