140 
THE NATURALISTS’ JOURNAL. 
had now been re-christened, carbonic anhydride, 'was then dealt with, and the 
impossibility of combustion in this gas experimentally shown. As was well 
known, it proved fatal to animal life when present in the air in sufficient quan¬ 
tity, and as it was given off by the lungs at each expiration, and also from gas 
and other flames, ventilation was absolutely a necessity in all rooms, shops, 
railway carriages, etc. This gas furnished us with a means of painlessly put¬ 
ting to death any animal we desired to kill, for its first effect was soporific, 
the animal dying while asleep. In this way mice and rats could be mercifully 
disposed of, and at the Dogs’Home, Battersea, thismethod was always employed 
in destroying all dogs it was deemed necessary to kill. The gas was heavier than 
air, and so could be poured from one vessel to another, and a soap bubble would 
float on it. After speaking, incidentally, of the remarkable discoveries of Prof. 
Dewar, the lecturer next discussed carbon, an element found commonly in all 
organic bodies, but seen in its purest form in the diamond, while coal and black 
lead (graphite) contained it in large amount, and it was of course one of the 
constituents of limestone and marble. Carbon was one of the most lasting of 
substances, which explained the great durability of a charred gate-post. The 
remainder of the lecture was devoted chiefly to the consideration of the occur¬ 
rence of calcareous compounds in nature, shells being shown to consist 
mainly of carbonate of lime, extracted, in the case of marine mollusca, from 
the sea water, in which it occurred by reason of its being brought down by 
rivers. Carbonate of lime deposited on the roofs of caverns by the percolation 
and evaporation of water formed the beautiful masses known as stalactites. 
The chalk and limestone rocks generally had been built up originally by 
marine animals. When water contained lime in solution, the addi¬ 
tion of carbonic acid gas produced a precipitate, and as this gas was con¬ 
tained in the breath this effect was easily brought about by blowing through 
a tube partly immersed in the water. Much amusement was caused by the 
lecturer’s imitation of a quack-pill vendor he had once encountered, who sought 
to turn this experiment to account by pretending that the precipitation showed 
the bad state of the lungs of the breather, who was thereby induced to purchase 
the remedial preparations offered ! 
On March 5th Mr. H. Wilson will lecture on “The Sun ” (with lantern 
illustrations), and on the 19th, the president, Mr. G. Masters, will read some 
additional notes on “ Garden Flowers,” which formed the subject of one of his 
recent lectures before the club. 
TO CORRESPONDENTS. 
G. W., Clapham.—We mentioned the fact of mice destroying eggs in No. 
11 of the N. J. (page 128) ; there is little doubt that they eat the contents, 
but as they more commonly invade “ domed ” nests it is probable that their 
purpose is also to utilize them as domiciles. 
E. B. L., Finsbury Park.—M. C. Cooke’s “ British Fungi,” with coloured 
plates, price 6/-, is the best book for you. It can be obtained from any 
Natural History agent or bookseller. Fungi may be preserved in weak (di¬ 
luted) spirits. 
W. G. C., Thetford.—We have many articles in hand and could not pro¬ 
mise inseition for two or three months. 
M. B., Abingdon ; E. B., Ipswich.—Shall be inserted. 
We have received a price list of rare British birds’ eggs from Mr. T. L. 
Cummins, of Bishop Auckland; and a catalogue of coleopterological works 
from J. B. Bailliere et Fils, 19 Rue Hautefeuille. Paris. 
Errata.— February No., page 109, lines 18 and 21, for “ Fir ” read “Fer.*’ 
