SCIENTIFIC SUMMAKY. 
325 
Pharmacy ” states that bromine was produced in America as early as 1846, 
for photograph purposes. "With the decline of the daguerreotype process the 
manufacture of bromine also ceased. In 1866 the employment of bromides 
in medicine renewed this branch of industry, the element being obtained 
from the mother liquors of the salt-works at Tarentum and Natrona in 
Alleghany. In 1868 an increasing demand led to its production in Penn- 
sylvania, Ohio, and Western Virginia. Between the years 1867 and 1873 
the amount produced rose from 5,000 to 88,000 kilogrammes. Up to the 
year 1870 the yield merely sufficed to supply the demands of the United 
States, and during that year bromine was first exported. Since that date 
the amount produced has steadily increased, and has so largely exceeded the 
demand that no new factories are now erected. 
GEOGRAPHY. 
Return of Lieutenant Cameron . — At the meeting of the Royal Geo- 
graphical Society, which took place on April 11, Lieutenant Cameron was 
gallantly received. The meeting was held in St. James’s Hall, which -was 
crowded by a large and fashionable audience. The chair was taken by 
H.R.H. the Duke of Edinburgh, who in the course of his opening remarks 
congratulated the navy on the fact that a member of it should have accom- 
plished so great a feat as Cameron’s journey from sea to sea was. Lieu- 
tenant Cameron then gave a brief resume of his journey from the East Coast 
to Ujiji, and thence across Lake Tanganyika to the West Coast. The main 
features of this narration have already been made known to the public 
through the pages of the u Geographical Magazine ” and “Proceedings” of 
the Royal Geographical Society. Regarding the interesting question of the 
outlet to Tanganyika, he stated that there was no place to which the 
Lukuga could flow except into the Lurwa, and that native information cor- 
roborated this view. Apart from the great difference between the volume 
of water of the Lualaba at Nyangwe and that of the Nile at Gondokoro, the 
levels proved conclusively that the two rivers could have no connection. 
He had seen a good deal of the slave-trade, and observes that the Portu- 
guese are the principal agents in the trade, the Arabs as a rule buying only 
enough slaves to act as porters and servants. The only effectual way 
of putting an end to slavery was to open up Africa to legitimate commerce 
by utilising the magnificent water-systems of the interior. Sir Henry 
Rawlinson expressed, on behalf of the council of the Society, a high opinion 
of Cameron’s services, which, besides their geographical importance, were 
equally interesting to the politician, the merchant, and the philanthropist. 
He had been almost continuously on the tramp for two years and eight 
months, during which he had been exposed to every kind of hardship, and 
had travelled over 3,000 miles. His observations, which numbered over 
5,000, were copious, elaborate, and accurate. Among the most noticeable 
of the results ot' his expedition were his exploration of the southern half of 
Lake Tanganyika and his discovery of the outlet, and his demonstration of 
the probable identity of the Congo and Lualaba. Another important result 
