454 
POPULAR SCIENCE REVIEW. 
up to that produced by KCIO3, may be obtained by gradually abstracting 
the KNO3 and supplying KCIO3 in its place ; so that by gradually increas- 
ing the temperature of the combustion, it was found that the order in which 
the lines made their appearance was — 1st, the line at 130, the line at 430, 
the triple line at 1,120, and the line at 3,100 ; 2nd, the triple line at 1,530 ; 
3rd, the triple line at 1,300 4th, the triple line at 1,760 j but the line in the 
blue remained invisible when the whole of KXO 3 was abstracted, and its 
place supplied by KCIO3. 
A neiv Gas Za7np, termed the Bourbouze, is now being used in France, and 
is said to be as brilliant as the oxyhydrogen light, and less expensive. Coal 
gas, intimately mixed with air, is urged with gentle pressure along a tube, 
and made to pass through a metallic plate pierced full of minute holes. 
By this means a vast number of jets are obtained, which, after being driven 
through a fine tissue of platinum wii’e, are lighted in the ordinary way. 
The platinum soon acquires a white heat, and gives out so brilliant a light 
that it cannot be supported by the naked eye. About one cubic metre of 
gas is consumed per hour. 
ZOOLOGY AXB COMPABATIVE ANATOMY. 
The Mole-rats . — M. Alph Milne Edwards has published a memoir on 
these creatures. He states that they afibrd an illustration of the fact, that 
the modifications by which animals adapt themselves to conditions of existence 
are given too great an importance by zoologists. Most zoologists,” he 
says, have ranged imder the same group the rodents which live under- 
ground, hollow out galleries in the earth by means of their claws, and feed 
upon the roots and bulbs of plants. These rodents have, in their general 
appearance, something which calls to mind the mole ; the body is more or 
less cylindrico-conical, and is borne on short stout limbs, and the eyes are 
frequently almost indistinct. Hence the group has been called the mole- 
rats. It is divided into a certain number of genera, as Bathyergus, GeorhycuSj 
Heliophohius, Spalax, Elohius, and Siphneus. The group thus formed is es- 
sentially artificial, and is composed of animals widely different. M. MUne 
Edwards then proceeds to demonstrate the errors of the naturalists who 
have considered this gro up, and to show how little affinity exists between 
certain of the species composing it.” — Comptes Bendas, August 17. 
The Aitijicial Inversion of the Viscei'a. — M. Dareste, who is certainly one of 
the most distinguished of modern teratologists, has made known the results of 
some very curious researches recently undertaken, to determine how far inver- 
sion could be effecte d by experimental means. The inversion of the viscera is 
very rare in man, and still rarer in the other animals. Indeed, prior to M. 
Dareste’ s observations, but one instance had been recorded, that of the 
embiyo of a fowl by Yon Bar. “The embryo,” says M. Dareste, “is in the 
commencement co mpletely symmetrical. It is only at a certain period of its 
evolution that it deviates from this arrangement; but this deviation may 
occur abnormall y, and then there is inversion of the viscera, or, more tech- 
nically, heterototaxyT M. Dareste adduces numerous facts to show that 
