502 pliny's katueal history. [Book XXXL 
mauner, too, it has been found in the thirsting deserts of 
Africa, as far as the oracle of HammoH,^^ a locality in which 
the salt increases at night with the increase of the moon. 
The districts of Cyrenaica are ennobled, too, by the production 
of hammoniacum,^^ a salt so called from the fact of its being 
found beneath the sands ^ there. It is similar in colour to the 
alum known as " schiston,"^ and consists of long pieces, by no 
means transparent, and of an unpleasant flavour, but highly 
useful in medicine ; that beiug held in the highest esteem, 
which is the clearest and divides into straight^ flakes. There 
is one remarkable fact mentioned in connexion with it : so long- 
as it lies underground in its bed* it is extremely light, but the 
moment it is exposed to the light, it is hardly credible to what 
an extent its weight is increased. The reason for this is evi- 
dent :^ the humid vapours of the excavations bear the masses 
upwards, as water does, and so aid the workmen. It is adulte- 
rated with the Sicilian salt which we have mentioned as being 
found in Lake Cocanicus, as also with that of Cyprus, which 
is marvellously like it. At Egelasta,^ in Nearer Spain, there 
is a salt, hewn from the bed in almost transparent blocks, and 
to which for this long time past most medical men, it is said, 
have given the preference over all other salt. Every spot in 
More commonly known as Jupiter Hammon. 
9^ See B. xii. c. 49, and B. xxiv. c. 28, for an account of gum resin am- 
moniac, a produce of the same locality. The substance here spoken of is 
considered by Beckraann to be nothing but common salt in an impure state. 
See his Hist, Inv. Yol. II. pp. 398-9, where this passage is discussed at 
considerable length. Ajasson, on the other hand, considers it to be Hydro- 
chlorate of ammonia, the Sal ammoniac. of commerce. According to some 
accounts, it was originally made in the vicinity of the Temple of Jupiter 
Hammon, by burning camels' dung. 
* Called dfjifiog, in Greek. 2 gg^ B. xxxv. c. 52. 
^ Sal ammoniac crystallizes in octahedrons. 
* Intra specus sues." On this passage, Beckmann says, From what 
is said by Pliny it may with certainty be concluded that this salt was dug 
up from pits or mines in Africa. Many kinds of rock-salt, taken from 
the mines of Wieliczka, experience the same change in the air ; so that 
blocks which a labourer can easily carry in the mine, can scarcely be lifted 
by him after being for some time exposed to the air. The cause here is 
undoubtedly the same as that which makes many kinds of artificial salt to 
become moist and to acquire more weight.** — Vol. II. p. 399, Bohn's Ud, 
^ According to modern notions, his reason is anything but evident. 
6 In Celtiberia. He alludes to the mountain of salt at Cardona, near 
Montserrat in Catalonia. 
