INDUSTRIAL PROGRESS DURING THE YEAR 1873. cxxiii 



during the past year to solve this j^uzzling problem. The 

 chief difficulty in the path of inventors in this field has been 

 the very important one of cost of production ; and it may be 

 said, without fear of contradiction, that the quality of the 

 material produced has been but a secondary consideration in 

 the question when compared with this. The last year has, 

 liowever, witnessed some great improvements in this direc- 

 tion, which have received a full share of public attention. 

 At the fair of the American Institute in New York, there 

 was on exhibition the model of a machine for producing ar- 

 tificial fuel which in some respects surpassed any thing hith- 

 erto devised. The process in question is the invention of Mr. 

 E. F. Loiseau, who has given many years' attention to the 

 subject. Thecorai^osition of the fuel is coal-slack and com- 

 mon yellow clay, moistened with milk of lime. The manu- 

 facture is carried on automatically, the crude materials enter- 

 ing the apparatus at one end, and emerging finished and ready 

 for shipment at the other. The only manual labor employed 

 is in supplying the crude materials. Great expectations are 

 entertained of the success of tlie process here alluded to. By 

 this process the lumps are made of egg-shape and water- 

 proofed, and as but five per cent, of clay is used to convert 

 them, the heating power of the product is not materially re- 

 duced. 



As the result of a series of researches upon proper fog-sig- 

 nals, made in behalf of the Light-house Board, Professor Hen- 

 ry has lately announced that the only instruments giving 

 sufficient agitation to the air, to be efficient for fog-signals, 

 are those in which the sound is reinforced by resounding 

 cavities. The simplest of these instruments is the ordinary 

 steam-whistle, those employed by the Board being from eight 

 to eighteen inches in diameter, with a corresponding height, 

 and driven by a pressure of steam of from sixty to seventy- 

 five pounds. This instrument has the advantage of giving a 

 sound of equal intensity in every azimuth. The DaboU air- 

 trumpet, in which the vibrations are produced by a steel reed 

 put in motion by air condensed by a caloric engine, gives 

 the greatest amount of sound with a given amount of pow- 

 er; but the instrument which exhibits the greatest penetrat- 

 ing power of sound, without regard to the energy expended, 

 is the siren trumpet, in which the ribrations are produced 



