348 



SCIENCE- GOSSIP 



CONDUCTED BY C. AINSWORTH MITCHELL, 

 B.A.OXON., P.I.C, F.C.S. 



Breathing under Water. — Some years ago a 

 diver's helmet was constructed by Mr. Fleuss with 

 the object of enabling the divers to be independent 

 of an external supply of air. In this apparatus 

 the exhaled carbon dioxide is absorbed by caustic 

 potash, whilst the oxygen consumed is replaced by 

 fresh gas from a small portable cylinder com- 

 municating with the helmet. The elhcacy of this 

 appliance has been frequently demonstrated by 

 Mr. Fleuss, but never in a more striking manner 

 than when he passed through the flooded Severn 

 tunnel, remaining under water for more than thirty 

 minutes. The helmet has also been adapted for 

 the use of firemen, who by its aid are enabled to 

 breathe in an atmosphere of thick smoke. A 

 simpler apparatus on the same lines has recently 

 been devised by Drs. Desgrez and Balthazar, of 

 Paris. The main feature of their invention is the 

 use of sodium peroxide, which was discovered in 

 1862 by Professor Vernon Harcourt, though it 

 has been but little used, except as a reagent in 

 analytical chemistry. Commercial sodium peroxide 

 is a yellowish-white powder, which is extremely 

 caustic and possesses strong oxidising properties. 

 On exposure to the air it absorbs carbon dioxide in 

 the same way as caustic soda, being converted 

 into carbonate, whilst on treatment with water it 

 is decomposed into caustic soda and gaseous 

 oxygen. Thus on placing sodium peroxide in con- 

 tact with water in an atmosphere that is being 

 breathed, the carbon dioxide will be continually 

 absorbed and the oxygen renewed by one and the 

 same substance. The apparatus applying this 

 principle contains a clockwork appliance by means 

 of which sodium peroxide is made to fall at regular 

 intervals to water, whilst the violence of the reac- 

 tion is moderated by a refrigerator. The apparatus 

 is contained in a light circular box of aluminium, 

 and is connected with the helmet by means of two 

 rubber tubes. With the aid of this " oxygen 

 generator " Dr. Balthazar has been able to remain 

 for more than half an hour in an atmosphere 

 saturated with sulphurous acid. 



Artificial Parthenogenesis. — Greeley has 

 discovered the interesting fact that it is possible 

 to efEect the development of the mature unfertilised 

 eggs of the starfish by exposing them in sea-water 

 to a temperature of 4° to 7° C. for one to nine 

 hours. Another striking fact in this connection is 

 the influence of potassium cyanide in prolonging 

 the life of the unfertilised eggs of the sea-urchin, 

 which has recently been demonstrated by Loeb 

 and Lewis. It was found that this salt, which is 

 ordinarily such a deadly poison, when added in a 

 small proportion to the sea-water apparently 

 efEected a suspension of the processes which cause 

 the death of the unfertilised eggs. Possibly these 

 processes are of an enzymic character presenting 

 an analogy to the so-called fibrine ferment, which 



is said to be the agent causing the coagulation of 

 the blood. It has frequently been shown that 

 potassium cyanide has a restrictive influence on 

 the action of various enzymes. 



" Red " Cod. — Minute red points resembling 

 vermilion have occasionally been observed on dried 

 salt cod, and in 1887 a whole cargo of fish at 

 Lerwick was thus infected. Dr. Edington found 

 the phenomenon was due to a micro-organism,. 

 Banllus ruhescens, which developed not only on 

 the fish, but also on the salt used by the curers. 

 When grown upon nutrient gelatin a wrinkled 

 colony was formed, in which a pink colour only 

 developed after some weeks. Though this micro- 

 organism was proved to be harmless, the fact of 

 its being present at all showed that the fish were 

 insufficientl}' preserved, and might thus become a 

 suitable medium for the development of pathogenic 

 bacteria ; and as a matter of fact several other 

 species of non-pathogenic micro-organisms were 

 isolated by Dr. Edington, although that mentioned 

 above was the only one that produced a colouring 

 matter. This bacillus is quite distinct from B.pro- 

 digiosvs, which forms a blood-red colony on moist 

 bread, and occasionally on meat. Dantec sub- 

 sequently found two chromogenic micro-organisms, 

 a bacillus forming terminal spores and a micro- 

 coccus, which produced a red pigment when grown 

 upon gelatin, but formed colourless colonies when 

 cultivated by itself upon salt cod. 



Action of Distilled Water on Lead. — Pro- 

 fessor Clowes has made a series of experiments to 

 determine the infliience of various salts and gases 

 upon the solvent action of water upon lead. From 

 the results obtained it is evident that carbon 

 dioxide has a restrictive influence, which is greater 

 in proportion to its quantity, whilst free oxygen is 

 the principal active agent. It was also found that 

 of the substances that prevent the solvent action 

 the most effective were sulphuric acid and sul- 

 phates, while lime (calcium hydroxide) was much 

 less effective, and when present in large quantities 

 even promoted the action. Distilled water, free 

 from dissolved gases, only dissolved lead to the 

 extent of 0-3 part per million when kept out of 

 contact with atmospheric oxygen. The amounts 

 of lead dissolved by the water in the presence of 

 oxygen and carbon dioxide were as follo'^\'s : — 





24 hours 



48 hours 



72 hours 



Oxygen alone 

 Carbon dioxide alone 

 Oxygen and Carbon dioxide 



in equal volumes 

 Oxygen and Carbon dioxide 

 '(S:l) 



Per cent. 

 0-013 

 0-005 



0-0U3 



0-015 



Per cent. 

 0-023 

 0-008 



0-003 



0-OlS 



Per cent. 

 0-029 

 0-017 



0-003 







Composition of Antique Statuettes. — An 

 interesting communication by M. Berthelot in a 

 recent issue of the " Comptes Rendus " shows that 

 the Chaldeans and Babylonians were possessed of 

 considerable metallurgical skill. A Babylonian 

 statuette was found to consist of a cojjper alloy 

 containing 79-5 per cent, of copper, 1'25 per cent, 

 of tin, and 08 per cent, of iron. A similar 

 statuette from Chaldea estimated to be 2,200 years 

 old was composed of nearly pure copper containing 

 only a slight proportion of iron, whereas another 

 Chaldean statuette, some 400 years older, consisted 

 mainly of an alloy of four parts of copper with one 

 part of lead and a trace of sulphiu-. 



