JANuaRY 21, 1897 | 
NATURE 
27.5 
On nearing the dark space, a decrease of temperature 
was always observed. The temperature was found to 
drop very suddenly on leaving the anode light, reaching 
a minimum near the middle of the dark space ; a rapid 
rise to maximum occurred as the blue negative light was 
entered. Witha pressure sufficiently reduced to cause 
the appearance of stra¢ifications in the anode light, the 
maximum was always to be found in the middle of the 
column, the temperature rising as the anode was left 
behind, and falling after the middle of the column was 
passed. In addition, “there is a periodic rise and fall, 
the light discs being warmer than the dark spaces be- 
tween them, although one often finds a point where there 
is no change of temperature on passing from a light 
space to a dark.” This last-mentioned fact is explained 
on the ground that the increase in the steepness of 
the curve as the maximum is approached, masks the 
comparatively small decrease due to the passage from 
the light to the dark interspaces. 
One of the many diagrams he reproduces, shows the 
temperature fluctuations in the stratified discharge at a 
low pressure of o11 mm. The ordinates 
edges of these strata further act as if they “had an 
elastic skin or a sort of surface tension, bending in as 
the wire pushes against them, and finally snapping back to 
their original positions, leaving the wire well within the 
luminous disc.” Mr. Wood, commenting on the results, 
considers that the curves obtained with the movable 
bolometer indicate with considerable accuracy the relative 
temperatures in the different parts of the discharge. 
THE TOMB OF LOUIS PASTEUR. 
PEN account of the impressive ceremony with which 
the remains of Pasteur were laid in their last 
resting-place at the Pasteur Institute was given in these 
columns on December 31, 1896. We are indebted to the 
Lancet of January 9 for the following full description of 
the tomb, and for the accompanying illustration, which 
is reproduced from a fine picture of the mausoleum of 
the great French investigator. 2 
The mausoleum is built at the end of a long corridor in the 
Institute, and is shut off by magnificent gates of wrought iron. 
increase for a rise in temperature, and 
the abscissz are longer the further the 
bolometer wire is away from the anode. 
The horizon of the diagram is taken as 
the temperature of the room, which in 
this case was 25°. Comparing the curve 
giving the fluctuations of the bolometer 
wire placed at points of different inten- 
sities throughout the tube (the latter being 
drawn parallel to the abscissa), many 
points of interest may be at once seen. 
Commencing at the anode, the curve on 
the whole is fairly horizontal, but rises 
wave fashion at every increase of lumin- 
Osity in the tube, dropping more or less 
suddenly as a dark space is entered. As 
’ the kathode is approached, the bolometer 
wire enters the large dark space; the 
curve falls somewhat abruptly down for 
some distance, rising again rapidly as the 
kathode is approached. 
It may be stated that the maximum in 
the anode light is less predominant here 
than it is at higher pressures, owing to 
the smaller changes of temperature. 
The periodic change in the strati- 
fied anode light was made the subject 
of a detailed investigation, more points 
of reference being taken. These results were also 
plotted in the diagram just mentioned (larger scale). 
“The temperature is steady for a certain distance, then 
rises gradually to a maximum, situated in the brightest 
part of the disc, turns and drops suddenly as we pass 
out of the sharply defined edge of the disc. The differ- 
ence of temperature between the light and dark spaces 
varies from 05 to about 1°°5, depending on the degree 
of exhaustion and current strength.” 
Assuming the electrical energy is wholly connected 
with heat, the temperature curves indicate for 
Positive light ... Medium potential fall .. Medium temperature 
Dark space... Small af 3 eee AO, 3H 
Negative light ... Large H High a 
a result which, as Mr. Wood says, agrees with what is 
already known. 
Two incidental points of interest mentioned refer to 
the behaviour of the strata. The movement of the 
bolometer loop from one stratum to another appears, at 
some pressures, to draw the stratum through which it is 
passing into the one immediately below it, the two 
dissolving into one, and the place left thus vacant being 
filled up by a new stratum springing off the anode. The 
NO. 1421, VOL. 55] 
Before describing it, it is interesting to note that it was built’ by 
the Pasteur family, and Monsieur J. B. Pasteur, the son of the 
great savant, suggested as a model the well-known tomb of 
Galla Placidia at Ravenna, which he had visited in the course 
of his travels in Italy. 
This tomb was built about 440 by the Christian Empress 
Placidia, the daughter of Thedosius the Great. It is in the 
form of a Latin cross 49 feet long and 41 feet broad, and we 
may refer to it in some detail to show how it inspired the 
architect of Pasteur’s tomb, Monsieur Girault. The interior of 
Placidia’s tomb is covered by mosaics, on a blue ground. 
Above the entrance are garlands of fruit and foliage ; and in the 
dome the symbols of the Evangelists. In the four arches which 
support the dome are figures of eight apc »stles, and between 
them is seen the familiar representation in mosaics of doves 
drinking out of a vase. Under the vaulting of the right and 
left transept are the other apostles, and, between them, stags. 
drinking at a spring in the midst of golden foliage. There are 
also designs in mosaic of branches of vines ; and two subjects, 
full of grace and dignity, the chef-d’aucres of Christian art in 
the fifth century, the first representing the Good Shepherd with 
His sheep, and the second representing the triumph of the 
Christian faith. The altar is constructed of oriental onyx, and 
behind it is the large marble sarcophagus, which was at one time 
enriched with plates of silver. 
Turning now to the Pasteur mausoleum, we find the archway 
