SCIENCE. 



433 



The pavilion of the City of Paris contains instruments 

 for the distribution of time and electrical instruments for 

 the service of the fire companies. This pavilion is sur- 

 rounded by the exhibitions of different French railroad 

 lines, which contain an enormous amount of apparatus 

 too complicated and too numerous to mention in this 

 short review. 



One of the most interesting' parts of the French exhibi- 

 tion is the pavilion of the Ministry of Posts and Tele- 

 graphs, which contains a complete collection of all the 

 modern apparatus employed in the telegraph service of 

 France. This pavilion is bounded on its North, South 

 and East sides by highly interesting collections of 

 different French firms, while on its West side the great 

 staircase leads to the upper stories. Of the exhibits 

 in the upper story I will give only a general catalogue 

 because the installments are as yet too unfinished to 

 render it possible to give any detailed description of them, 

 and the experiments with the electric lights and tele- 

 phones, to which this portion of the palace is mostly de- 

 dicated, will not commence before eight days. 



Hall A, immediately opposite to the grand staircase, is 

 a beautifully furnished drawing room called the " Salon 

 du President " and will be lighted by the Werdermann 

 light. 



Hall i contains a gallery of paintings but it is to be 

 hoped that the light of the " Lampe-Soleii " which is here 

 exhibited will be better than the pictures, which are 

 wretchedly bad. 



Hall i contains a stage which once figured in the, so- 

 called, " Athenasum," in the " Rue des Martyrs." This 

 stage will be used for showing stage effects produced by 

 electric lights, and the light will be furnishtd by the 

 Werdermann Company. 



Hall 3 is a tastefully furnished dining-room, with table 

 temptingly set, in which the Werdermann light will also 

 be displayed. 



Hall 4 is an apartment consisting of vestibule, kitchen 

 and bathing-room, which will be lighted by incandescent 

 lamps fed from reservoirs consisting of Faure's secondary 

 battery and furnished by " La Societe de la Force, et la 

 Lumiere." 



I have made it a special object to study the value of 

 the Faure-battery in regard to which so much has been 

 said pro and contra, and propose to furnish your excel- 

 lent paper with impartial reports on this subject as 

 soon as any definite knowledge of it can be obtained. 



Halls 5 and 6, which are united in one, will display 

 lights of the " Systeme-Jamin " and contain a collection 

 of Gramme-machines modified by M. Jamin. 



Hall B contains a collection of smaller electrical ap- 

 paratus, of electrical toys and also an exhibition of Jab- 

 lochkoff candles. 



Halls 7 and 8 are dedicated to telephone experiments, 

 hall 7, being lighted by " La Societe de la Force et la 

 Lumiere " while the light of hall 8, is furnished by Mr. 

 Brush. The preliminary experiments with the telephones 

 in these halls have been exceedingly satisfactory, the music 

 of the Grand Opera and the words spoken in the 

 " Theatre-Francais " (both of these buildings being con- 

 nected by telephone-wires with halls) can be so plainly 

 heard that one may really imagine himself to be one of 

 the audience present, instead of being several kilometers 

 distant from the places of performance. A person, who 

 has never witnessed these telephone experiments can 

 have no idea of the value of the microphone and tele- 

 phone, and the public, before which these experiments 

 will be made in about eight days, will be greatly aston- 

 ished to see those reports verified which it has hitherto 

 taken for exaggerated descriptions of sanguine writers. 



Hall 9 contains chiefly electrical apparatus devoted to 

 medical purposes, and will be lighted by Meritens, who 

 also has there exhibited the most of his special apparatus. 



Hall io is dedicated to the exhibition and the light of 

 the firm of " Sautter et Lemonnier." 



Hall ii has Jablochkoff light and will also exhibit the 

 apparatus used for photographing by electric light. 



Hall 12 will be lighted by the Spanish society of elec- 

 tricity which employs Gramme's lamps. 



Hall 13 serves for the display of Siemens' differential 

 lamps and contains an excellent collection of instruments 

 of precision and of Geissler tubes. 



Hall 14 contains machines of the system Wilde and 

 Alliance, it will be lighted by means of Wilde's candles, 

 furnished by the Parisian Company of Wilde's light. 



Hall C contains cables, telephones, and telegraph in- 

 struments and will be lighted by incandescent lamps of 

 Maxim furnished by the United States Electric Lighting 

 Company. 



Hall 1 5 has, among other things, a nice collection of 

 lightning-rods and contains Jaspar's light. 



Hall 16 has lamps of M. Anatole Gerard. 



Hall 17 contains electro-chemical instruments, appara- 

 tus for galvano-plastics, etc., and lamps of the Gramme 

 system. 



Hall 18 contains a highly interesting museum of histor- 

 ical instruments of electricity. The light is furnished by 

 Messrs. Mignon and Rouart. 



Hall 19 will be lighted by a company from Lyons, display 

 ing the processes of Lontin, Bertin and Mersanne, and also 

 contains the electro-pneumatic clocks of Mr. Mayrhofer, 

 which form one of the most interesting parts of the elec- 

 trical exhibition. 



Hall 20 contains a retrospective museum and a library 

 of works on electricity ; the light in the former will be 

 furnished by Mr. James Fyfe, that in the latter by Mr. 

 Daft. 



Hall 21 serves as a restaurant and is ornamented by a 

 large chandelier containing Swan's incandescent lamps. 



Hall 22 serves as a reading-room and will be lighted by 

 the Brush system. 



Hall D is the place where the Congress will meet, and 

 halls 23 and 24 contain the exhibition of Edison, of which 

 I shall not now speak in detail, reserving a description for 

 a special letter, when I will attempt to do justice to this 

 interesting exhibit. Gustave Glaser, Ph. D. 



Paris, August 17, 1881. 



THE AMERICAN CHEMICAL SOCIETY. 



The first meeting of the American Chemical Society, 

 after the summer vacation, was held on Friday evening, 

 September 2, with Vice-President Leeds in the chair.' 

 The minutes of the previous meeting were duly passed 

 on and Dr. H. Endemann elected to the position of 

 Editor of the Journal. The first paper presented to the 

 Society was "On the Detection of Oleomargarine," by 

 Mr. P. Casamajor. This method is based on the differ- 

 ences between the density of butter and oleomargarine. 

 A drop of the suspected fat is melted and poured into 

 alcohol at i5°C ; if it is butter, on account of its greater 

 specific gravity, it immediately sinks to the bottom of 

 the vessel, while if it is oleomargarine it remains on the 

 surface. 



Mr. Casamajor followed by • a second paper on the 

 " Detection of Sugar House Syrups from Starch Sugar 

 Syrups." The author found that by dissolving the given 

 sample (ioc.c. are taken) in three times its volume of 

 methylic alcohol, the ordinary sugar syrup will become 

 entirely dissolved, while the starch sugar syrup becomes 

 precipitated under the same conditions. Partially dis- 

 solving indicates, of course, a mixture of both. 



" A Short Table for Testing Sugar by Inversion " was 

 the title of the third paper. It was also by Mr. Casa- 

 major. Assuming that D = the first deviation in a 

 reading of a polariscope and — D' the second, substract- 

 ing them we have D + D'. 



t = the temperature. 



When a solution of pure sugar is 100, the sum of the 

 two readings will equal 144. Making A equal to the 



