November 1, 1886.] 



♦ KNOWLEDGE ♦ 



17 



effectually prevent both of these evils, and to gain fresh 

 light, Dr. Sir William Siemens and Herr F. Siemens 

 conducted a series of exhaustive experiments, with the 

 result which is now known as the " Regenerative System," 

 which consists in supplying the flame with heated air 

 and gas to enable it to effect complete decomposition 

 of the carboniferous gas. " The apparatus comprises three 

 parts : the biu-ner proper, the regenerator (in which the 

 gas and air necessary for the combustion is previously 

 heated) in contact with the sides of the flue, which sucks 

 down and carries oti" the products of combustion. The 

 burner is formed by a ring of small vertical copper tubes of 

 about tbi-ee-sixteenths of an inch in diameter, and of which 

 the number varies from sixteen to thirty-two, according to 

 the size of the apparatus. The gas, in passing up these 

 tubes, becomes still more heated without acquii-ing a suffi- 

 ciently high temperature to become decomposed. The rela- 

 tively large diameter of the burner tubes has the double 

 advantage of preventing any deposit of soot and of check- 

 ing the too rajiid flow of gas. The products of combustion 

 are continuously returned l:>y a downward current to the 

 interior of the bui'ner itself, and there utilised to heat fresh 

 gas and air prior to use. The result is that combustion by 

 this method is absolutely perfect.* These regenerative gas- 

 burners need not be ungainly in ajjpearance ; on the con- 

 trary, there is even scope for increased elegance of design. 

 It may be worthy of suggestion here that the fittings of the 

 laboratory ought always to embriice artistic principles where 

 practicable, for labour, like digestion, is accelerated when 

 general sensation is rendered suitabh' pleasant. 



The incandescent electric light in vacuo, however, mtist 

 be acknowledged, tuia voce, to be the best for all domestic 

 purposas, including the illumination of the laboratory, since 

 it cannot impair the atmosphere by consuming oxygen and 

 emitting injurious products. Its invention by Swan and 

 Edison in 1877 now bids fairly to supersede the employ- 

 ment of all other illuminants, but the costliness of the 

 methods in use, and the many technical difficultias yet to be 

 overcome in its several practical applications and the efficient 

 education of workmen and others, makes its universal intro- 

 duction even in London for many years to come extremely 

 problematiail. For these reasons the subject of lighting 

 with oil and gas has been treated of in detail, and it is 

 probable that with the spread of knowledge of the principles 

 of thorough ventilation and warming in relation to the forms 

 of apparatus now used, e.(j., the "Defries" lamp, the "Albo- 

 carbon," " Omega," " Carburetter," and " Siemens's Eegene- 

 rative Burner," that oil and gas will continue to hold their 

 places indefinitely as domestic illuminants. 



Under the heading of " Hygienic Comparisons between 

 Gas and Electric Litrht." the following extract Ls at least 

 noteworthy : — " Some interesting experiments, we learn 

 from the Builder, have been recently made at the Royal 

 Theatre, Munich, in order to determine the elevation of 

 temjieyature and amount of carbonic acid generated imder 

 illumination by gas and the electric light respectively. 

 Before the performance commenced the cuitain was raised, 

 and all the lamps allowed to burn for an hour, at the end 

 of which time the temperature was observed at intervals of 

 five minutes simultaneously in the parquet, balcony, and 

 third gallery. During the performance, when from five 

 hundred to six hundred persons were in the theatre, the 

 thermometer was observed every ten minutes. The experi- 

 ments showed that the electric light greatly diminishes the 

 increase of temperature. It does not render ventilation 

 superfluous, but it requires a less active ventilation than 



1S82. 



' Gas Lighting of the Future," pp. 2, 3. 2nd edit. London : 



gas, since it does not, like gas, contribute to the increase 

 of heat and carbonic acid.* 



With all the appliances above mentioned in good working 

 order, there yet remain many seemingly tri\aal items to be 

 carefully attended to in shielding the laboratory from the 

 incursion of dust and dirt, undue moisture, and other things 

 which have a direct bearing upon the comfort as well as the 

 health of the student. The prevalent forms of wall decora- 

 tions and floor coverings employed seem to be especially 

 adapted to the accumulation of filth, whilst many of them 

 are active disea.se-producing agents. Undue moisture in the 

 air is well known to be a fertile cause of failure in delicate 

 experiments — e.g. the pure culture of germs, and the pre- 

 servation of implements, books, chemicals, itc, from pre- 

 mature oxidation, mouldy gi-owths, and general decay. 

 Moist air thus operates powerfully in physical disintegration, 

 and in supporting myriads of objectionable organic creatures. 

 The remedy need not be expensive, although a costly initial 

 outlay would be s;iving in the long run, in consideration of 

 its permanent value. 



All the woodwork, both exposed and hidden, ought to be 

 rendered impervious and stable by being suitably painted or 

 varnished. This applies as much to the flooring as to the 

 doors, cupboards if any, window-frames, and wall-.skirtings. 

 Furniture, as a rule, is always so treated, with but few 

 exceptions, to be noted in the sequel. The paint selected 

 should be non-poisonous,t fire and damp proof, washable, 

 perfectly adhesive with a good body, and not liable to scale 

 off or blister through changes in the weather, itc. The 

 hai-mless basis known as " Charlton white " may be used in 

 place of the poisonous white lead, and care should be taken 

 to procure non-poisonous driers for use with it. All the 

 good qualities noted, however, are exemplified in "Thompson's 

 magnetic oxide of iron paint " and " granitic paint," with the 

 exception of fire-protective property ; the latter can be 

 additionally secured by the preliminary use, as a priming, of 

 the " Patent Liquid Fireproof Cyanite." For the ceiling a 

 washable sanitary distemper, such as the " Silicate Zopissa 

 Composition," ought to be used. 



The walls of the laborator}' should preferably be painted 

 with some one of the materials alreadj' mentioned, and, as 

 the selection and blending of colours can lie very tastefully 

 displayed, wall-papers may be dispensed with. Paper, how- 

 ever, is much cheaper than paint, and affords a much larger 

 field for artistic skill ; but health and comfort must not give 

 place to the false economy of cheap poisonous wall-papers. 

 Wheie paper is used the wall ought to be previously lined 

 with an impervious film or coat. " Silicate Zopissa Com- 

 position " or " Eastwood's Damp-proof Paper " may be used 

 profitably as stib-linings. The paper itself should be non- 

 pioisonous, washable, and free from rough embossed or similar 

 raised work, which is liable to harbour dust. Any kind of 

 paper can now be procured or rendered washable by the 

 leading dealers in such things. Arsenical papers shottld be 

 avoided ; they are not neces.sarily green in colour — indeed 

 the opposite is now generally found to be the case. It is well 

 known that arsenic, when taken internally in homceopathic 

 doses, is an excellent tonic and skin-purifier, and ]Mattieu 

 Williams has doubted whether arsenical wall-papers may not, 

 instead of being injurious, prove actually beneficial ! There 

 is much truth in the question thus raised, and many arsenical 

 wallpapers may distinctly be shown to be health-giving ; 



* "The Illustrated Science Monthly," London, April 1885, vol. iii., 

 p. l-'O. 



f It has been urged tliat poisonous painis, such as white lead, 

 the basis of ordinary shades of colours, are harmful only when wet, 

 but apart from the "fact that this is not strictly true, that circum- 

 stance alone should be a sufficient condemnation, most of all in the 

 interests of oiir labourins artists. 



