5IO 



NATURE 



{Oct. 5, 1876 



Janssen spoke in the name of the Meteorological Society 

 of France, described the celebrated experiment which 

 Pascal made on the mountain and the barometer which 

 he used, and showed what science owes to the observa- 

 tions made with this precious instrument. He at the 

 same time announced that the Meteorological Society 

 had awarded to M. AUuard a first silver medal. Many 



other eloquent speeches were made, in all of which reve- 

 rential reference was made to the immortal Pascal. 



The observatory consists of two distinct parts — the 

 house of the keeper and the meteorological building. 

 The former comprises, first, the telegraph office, from 

 which messages are sent to the station on the plain, and 

 alongside of which are apartments for the keeper, who has 



Fig. 2.- — Puy-de-D6me Observatory on the Day of its Inauguration, August 22, 18 



been chosen by M. Alluard from the navy. On the first 

 floor are apartments for th£ director, and several rooms 

 reserved for savants who may wish to sojourn on the 



J^ RuinesdeUChapeHe 

 S'Barnabe 



D.rection^eOier- 



Fifi. 3.— Plan of the Puy-de-D8me Observatory. 



sumrnit of the peak to carry on observations. The body 

 of this building communicates with the meteorological 

 building by a subterranean tunnel. The latter building 



comprises an underground floor built above a vault, and 

 another upper story which is on a level with the summit 

 of the peak. 



Traversing the tunnel from the house of the keeper, 

 we reach the lower part of the meteorological building ; 

 this is a vault into which the light of day does not pene- 

 trate. It is intended for the magnetic chamber, and will 

 be kept dry by a thorough ventilation, the walls being 

 covered with cement. The first floor above this, is also 

 underground, but is provided with two holes, by which 

 the light enters. It constitutes a circular chamber, sur- 

 rounded by a corridor, for the purpose of enveloping it 

 in a layer of insulating air. Here will be placed the 

 apparatus, the regular working of which requires a con- 

 stant temperature, and among which we may mention 

 Redier's registering barometer. The upper story, as we 

 have said, is level with the ground, and forms a beautiful 

 building, provided with four windows, adjusted to the 

 four points of the compass. It communicates with" a 

 small external louvered cage, containing the various 

 classes of thermometers. Inside are the following instru- 

 ments :— (i) M. Hervd Mangon's anemograph, communi- 

 cating by electric wires with the Robinson anemometer, 

 placed on the top of the fixed mast on the upper part of 

 the tower ; (2) Mangon's register or pluviometer ; (3) M. 

 Hasler's thermohygrograph ; (4) Fortin's and Tonnelet- 

 Renou's barometers ; (5) regulating clock ; (6) astrono- 

 mical telescope. This portion of the building is furnished 

 with tables placed between each window. 



Independently of the observations recorded by the 

 registering apparatus, the keeper makes observations 



