DR. O’SHAUGHNESSY’S EXPERIMENTS A T THE GOVERNMENT HOUSE. S91 
CHARACTERS OF EMBI A, A GENUS OF 
INSECTS ALLIED TO THE WHITE 
ANTS (TERMITES), WITH DESCRIP- 
TIONS OF THE SPECIES OF WHICH 
IT IS COMPOSED. 
By J. O. Westwood, Esq., F. L. S. 
This genus is remarkable at present not 
only because it consists of species nearly 
allied to the white ants, but because it is com- 
posed of 3 exotic species, each from a dif- 
ferent quarter of the globe, wdiile a single 
specimen only of each has hitherto come under 
the observation of entomologists ; each pos- 
sesses also characters of a higher rank than 
mere specific distinction, whence he has been 
under the necessity of considering each as a 
distinct subi^enus ; these are Ernbia Savignii, 
Oligotoma Saundersii, anil Olynthia Brazi- 
liensis. Mr. Westwood has also observed 
two species imbedded in Gum Copal or Anime, 
which he has not been able sufficiently to iden- 
tify. 
ON A NEW ARACHNIDE UNITING 
THE GENERA GONYLEPTES AND 
PHALANGIUM. 
By THE Rev. F. W. Hope, M. A., 
, F. R. S., F. L. S. 
This remarkable insect with disproportion- 
ally long hinder legs, so long that it is dif- 
ficult to conceive of what utility they can be» 
was collected in Brazil by the late Mr. Ha- 
worth, a zealous promoter of entomology in 
all its branches. Mr. Hope terms it Dolichos- 
eelis Haworthii. 
ZOOLOGY. 
DESCRIPTION OF A NEW SPECIES OF 
THE GENUS CHAMELEON. 
By Mr. Samuel Stutchburg, A. L. S.. &c. 
CHAMELEON CRISTATUS. C. Super- 
ciliari occipitalique carina elevata et crenulatfi> 
caudae anteriori parte dorsique anophysibas 
elongatis cristam dorsalem constituentibus : 
squamis fere rotundis subsequalibus. The 
striking peculiarity of this animal consists in 
its having a dorsal crest, supported by the 
spinous processes of the vertebrae, by which 
character it approaches the basilisks. It was 
brought from the banks of the river Gaboon 
in Western Equinoctial Africa, and was pre- 
sented to the Museum of the Bristol Institu- 
tion, by Messrs. King and Sons of that city. 
THE PRACTICAL MECHANIC’S POC- 
KET GUIDE, &c. 
By Robert Wallace, a. M., Glasgow, 
1836. p. 120. 
This is a very neat and useful little com- 
pendium of the most important rules for the 
practical mechanic, arranged under the heads 
of 1. Prime movers of machinery; 1st. Ani- 
mal power. — ^2d. Wind power. — 3rd. Water 
power. — 4th. Steam power. II. Weighty 
strength, and strain of materials. III. Prac- 
tical tables : let. Weight of metals.-~-2jxd. 
Specific gravity and weight of materials.— 
3r(l. Steam and steam engines. — 4th. Spe- 
cific cohesion and strength of materials. — 5th. 
Mechanical powers. The section upon steam 
is illustrated by a good plate of the steam 
engine, and . a plan is appended to the work 
of the land which has been drained behind 
the town of Greenock, and of the great reser- 
voir which is supplied by these numerous 
drains. We have no doubt that Mr. Wallace’s 
book will be duly appreciated by those for 
whom it is intended, and we recommend it to 
the attention not of mechanics alone, but of 
all who are interested in this importaot 
branch of philosophy. 
THE INDIA REVIEW. 
Calcutta : December 15, 1836. 
LORD AUCKLAND’S SCIENTIFIC 
PARTY. 
Dr. O’ Shaughnessy demonstrated by ex- 
periments the nature and properties of 
oxygen and hydrogen gases, and the com- 
position of water, by introducing them in 
aclose glass vessel, theinside of which, though 
clean and dry before the experiment, became 
dewy. This was done with Cavendish’s ap- 
paratus, by exploding the mixture with an 
electrical spark. Dr. O’ Shaughnessy took 
that opportunity of bringing to the notice of 
his hearers that, within a week past, he had 
received information of a new experiment, 
by which it was shown that hydrogen gas 
was a complete test for arsenic, which Dr. 
O’ Shaughnessy considered an invaluable 
discovery* 
He placed a few drops of Fowler’s solution 
in a vessel with water, and obtained hydrogen 
by solution of zinc in sulphuric acid. The 
hydrogen being ignited was allowed to 
play in a small jet in a glass tube; where 
Dr. O’ Shaughnessy supposed it deposited 
the arsenic. 
Fresh lime water, added to a fluid con- 
taining arsenic, is said to have precipitated 
l-30th of a grain of the metal. But Dr. 
O’ Shaughnessy thought that hydrogen gas 
would detect the 500th part of a grain. 
We suppose this experiment has originated " 
from the well known test of water saturated 
xritii sulphurretted hydrogen gas, formedi by 
the actio n of diluted muriatic acid on sulphu- 
