THE YOUNG SCIENTIST. 
305 
scattered about the bottom of the cage as 
well as the sand. 
Anything of the nature of a narcotic 
militates against the chances of life in 
parasites ; it is a good i^lan, therefore, to 
hang a small bag of camphor in a corner 
of the cage nigh to the nest. It is as well, 
too, when the young birds are about half 
fledged, to give them a clean nest, de- 
stroying the lining of the old one, and 
putting the box aside for disinfection and 
cleansing. 
The eggs take, as I have already told 
you, thirteen days to hatch ; and when 
the birds are about thirteen days old, the 
mother thinks she would like to begin to 
l^repare for another family. Give her, 
therefore, another nest and some nesting- 
material, else it is possible that the hen 
may attempt to line her nest-pan with 
the feathers of her progeny. This is 
what fanciers call plucking the young. 
If she persists in helping herself to the 
feathers of her young, they must be 
placed in a small cage, secured against 
the breeding-cage in such a waj^ that the 
parents can get through their heads and 
necks to feed them. Or the male bird 
may be turned in for. a time ^\ith the 
young; he generally makes a very ex- 
cellent nurse. But my intelligent young- 
readers will naturally observe, that if the 
hen has begun to prepare for a new 
brood, the attendance and supervision of 
the male will be wanted in the breeding- 
cage. This is perfectly true, and the 
difficulty is got over in this way by 
breeders : they turn the male into the big 
cage with the hen night and morning for 
an hour, or less. As soon as the hen has 
laid her third egg, the male may be re- 
tained as nurse only until the day of 
hatching, by which time the former 
brood will be able to pick for them- 
selves. 
Remember, however, that it is not very 
often neccessary to remove the young 
birds from the parent cage until the new 
brood is actually born, or on the eve of 
being so. They are then to be turned 
into a cage by themselves, and the more 
roomy this is the better, for young birds 
need exercise. 
(To he coniinued.i 
An Arabic Celestial Globe of the 
Eleventh Century. 
N the philosophical cabinet of 
the Eoyal Institute of Florence, 
many of "the iustruments of 
Galileo and other students of 
astronomy and physics are preserved. 
Among them is an Arabic celestial globe, 
of which F. Meiissi has published an in- 
teresting description. It has not been 
long in possession of the Institute, and 
no one suspected its antiquity until re- 
cently. The one which is in the Borgian 
Museum, at Yelletri, which was described 
by Assemani, in 1790, and which dates 
from the year 1225, has hitherto been re- 
garded as the oldest. There are two 
others of the same century, one of A.D. 
1275, owned by the Royal Asiatic Society 
of London, and the other of A.D. 1289, in 
the Mathematical Saloon at Dresden. 
There are also two, one owned by the 
Royal Astronomical Society of London, 
and the other by the National Library of 
Paris, both of which are without date. 
Menssi's curiosity was first awakened by 
observing that the longitude of the stars 
showed that the globe must have been 
constructed about the year 1075. On 
closer examination, he found an Arabic 
inscription around the Antarctic Circle, 
which he submitted for translation to the 
leariied Orientalist, Prof. F. Lasinio. He 
presented a note to the Society, in a 
meeting which was attended by the Em- 
peror of Brazil, in wdiich he stated that 
the inscriptions were in Cuflr characters, 
and that the globe was made by Ibra- 
him Ihn Said as-Sahli and his son Mo- 
hammed; the work was finished in 
Valenza, in the beginning of the month 
of Safor, in the year 473 of the Hegira 
(corresponding to the 22nd of July, 1080)." 
The diameter of the globe is 209 mil- 
limetres (8'23 inches). It is composed of 
two hemispheres of brass, soldered to- 
gether, and it gives the arrangement of 
stars and constellations which was 
adopted by Ptolemy. Among the South- 
ern constellations, the Cup (Cratern) 
which should have been placed between 
the second and third coils of the Hydra, 
is wanting; all the other constellations 
