64 ANNUAL OF SCIENTIFIC DISCOVERY. 



The ventilation is provided for by an opening, having an area 

 of 120 square feet, for the escape of the vitiated air, which is 

 formed in the centre of the ceiling at the highest possible level. 

 This opening is surmounted by a shaft rising some feet above the 

 roof, and which is fitted with regulating louvres. The heat gen- 

 erated by the system of lighting the hall will increase the suction 

 of this shaft at night. During day performances, however, con- 

 tinuous circulation will be insured by a ring of gas-jets from burn- 

 ers with which the shaft is provided. 



From a recent visit to the Albert Hall, we are enabled to re- 

 port the satisfactory progress of the building generally, under 

 the able superintendence of Colonel Scott, R.E. With regard to 

 Mr. Phipson's arrangements, we found that the pipes for heating 

 were all fixed in the outer circle main heating-chamber, and the 

 connections were being made with the steam-pipe to the condens- 

 ers. About one-third of the inner circle-chamber is completed, 

 and the remainder of the work is progressing. On Wednesday 

 week the wedges between the crown of the roof of the hall and 

 the scaffolding which had previously supported it were struck. 

 The results of this operation were highly satisfactory, the total 

 deflection being only five-sixteenths of an inch. The roof, be it 

 remembered, is of wrought iron, and covers an elliptical area of 

 220 feet by 185 feet, with a rise of 33 feet. Scientific Ameri- 

 can. 



HEAT BY MEANS OF ILLUMINATING GAS. 



" Gas, as a combustible," said M. Cazin, at a recent scientific 

 conference, " offers the best solution of the problem of distribution 

 of motive power in large towns where the illumination by gas is 

 already established. The pipes which furrow our cities convey 

 a provision for light, for heat, and for motive force. We de- 

 manded primarily of the gas the first of these agents ; we have 

 demanded also the second ; it is now time to demand of it all that 

 it is capable of affording. Why should not the same apparatus 

 afford to the workman in his shop light, heat, and power ? When 

 gas becomes cheaper this remarkable amelioration of the lot of 

 the artisan will be realizable." We will add that the obstacles to 

 the employment of gas as a source of motive power arise not 

 only from its high cost, but also from its disagreeable odor, and 

 the absence of proper means for good combustion. The odor 

 which is produced chiefly at the commencement of the operation 

 is produced by condensation of some of the products of the com- 

 bustion upon a cold surface. It may be prevented in a great 

 measure by previously heating the generator with another com- 

 bustible. With regard to an efficacious burner, we do not know 

 of any ; Bunsen burners, which are generally preferred, afford 

 hardly one-half the calorific power contained in the gas. The 

 Parisian Company have directed a series of trials upon the calo- 

 rific capacity of illuminating gas, which give sensibly the same 

 results. Copper tubular boilers were employed of a capacity of 

 10 to 30 litres. The heat was obtained from 2 Bunsen burners 



