252 EVANGELICAL ASSOCIATION. EXHIBITION OF ELECTRICITY AT PARIS. 



power for operations requiring an elevated 

 temperature. With mirrors of 80 centimetres 

 diameter, he obtains 400 or 500 centigrade 

 of heat, sufficient for the calcination of alum, 

 the preparation of benzoic acid, the sublima- 

 tion of sulphur, the distillation of sulphuric 

 acid, for concentrating sirups, refining linseed- 

 oil, making charcoal in closed vessels, and 

 other such processes. His small solar alem- 

 bics he can use for distilling essences, for heat- 

 ing the sand-bath, and similar objects. The 

 rays are brought to a focus upon the alembic 

 by the concave mirror. The great mirror of 

 Mouchot has a diameter of 3'80 metres. The 

 form of concentrating mirror used at first did 

 not utilize more than 50 per cent of the solar 

 heat. The new form, devised by Abel Pifre, 

 gives back 80 per cent of the total possible 

 heating effect. The older one was conical, 

 while the new form approaches the parabola, 

 the generatrix being a broken line forming 

 three truncated cones, the middle one having 

 its sides inclined to the axis 45, the same 

 angle as in the simple truncated cone used 

 in the older form. This reflector presents to 

 the sun an effective area of nine square metres. 

 The boiler, holding 50 litres, is brought to a 

 boil in 50 minutes, and the pressure then rises 

 at the rate of one atmosphere every seven or 

 eight minutes. With this apparatus Mouchot 

 has obtained six times the useful effect given 

 by the other. With a steam-engine of special 

 construction, made movable in its bed to cor- 

 respond to the direction of the reflector, 100 

 litres of water per minute are raised three me- 

 tres. A motor of one horse-power has been 

 constructed, the reflector of which has at its 

 opening a diameter of 5 metres, or an area of 

 incidence of 20 square metres. 



EVANGELICAL ASSOCIATION. The fol- 

 lowing is a summary of the statistics of this 

 Church, as they were published in August, 

 1881: 



* The report of this conference is included in that of the 

 Des Moines Conference, from which it has been taken and 

 organized. 



Number of local preachers, 611 ; Sunday- 

 schools, 2,016, with 21,773 officers and teach- 

 ers and 127,557 scholars ; number of baptisms 

 during the year, 1,328 of adults and 7,828 of 

 children ; probable value of the 1,534 churches, 

 $3,350,485 ; number of parsonages, 456, of a 

 probable value of $431,810 ; amount of " con- 

 ference contributions," $5,313 ; of contribu- 

 butions for missions, $92,740 ; of contributions 

 for the Sunday-school and Tract Union, $2,773. 

 The increase in the number of members during 

 the year was 1,674. 



EXHIBITION OF ELECTRICITY AT 

 PARIS. Among the notable events of the 

 year was the International Exhibition of Elec- 

 tricity opened in Paris, August llth, in the 

 Palace of Industry, in which the World's Fair 

 of 1855 was held. So rapid has been the de- 

 velopment of electrical appliances in recent 

 years, that this great building, with its forty- 

 five thousand square metres of space, barely 

 sufficed for the present display. Indeed, a 

 number of pavilions were erected without its 

 boundaries by numerous exhibitors. The dif- 

 ferent countries were very fully represented, 

 the largest and most varied exhibit being made 

 by France, which occupied as much space as 

 all the rest of the exhibitors ; England, Ger- 

 many, and America being next in order. While 

 the exhibition was devoted to electrical applU 

 ances of all kinds, the chief feature was un- 

 doubtedly the larga and varied display of elec- 

 tric lighting the lamps of both the arc and 

 incandescent type, the machines for generating 

 the current, and the many details of a com- 

 plete system of this mode of illumination. In 

 the main hall, a large rectangle, two hundred 

 and fifty metres long by one hundred broad, 

 all the various forms of lamps were commin- 

 gled, producing a dazzliug glare of light, that 

 rendered comparison impossible. But in the 

 smaller saloons reserved for the different ex- 

 hibitors, only the special lamp of each exhibit- 

 or was shown, allowing of a correct estimate 

 of each form of light. The display of lamps 

 of the arc type was very full, all of the now 

 well-known, as well as a number of more re- 

 cent, lamps being shown. The interest, how- 

 ever, centered upon the systems of incandescent 

 lighting, examples of which were exhibited by 

 Messrs. Edison, Maxim, Swan, and Lane-Fox. 

 The arc had already made for itself a perma- 

 nent place, but about the incandescent lamp 

 there was much doubt. This has been very 

 largely removed by the excellent showing 

 made by these lamps at the exhibition, and 

 several prominent electricians, who have looked 

 with great disfavor upon this method of illu- 

 mination, have in consequence announced their 

 belief that the problem of household illumina- 

 tion by electricity, if not solved, is at least very 

 near a solution. The most complete of the ex- 

 hibitions of incandescent lighting was that of 

 Mr. Edison, whose system, from the lamp to 

 the conductors, was shown in detail. A thou- 

 sand lamps, three hundred in the two saloons 



