380 
POPULAR SCIEL^CE REVIEW. 
The Deposition of Metals by a new process lias been discovered by M. Well, 
a French chemist. The baths he employs consist of metalhc salts or oxides, 
in alkaline solutions, by means of glycerine, albumen, and other substances, 
which prevent the precipitation of the oxide by the fixed alkali, in some cases 
with, and in others without, the aid of zinc or lead, and at various tempera- 
tures, according to circumstances. The discoverer asserts too, that by these 
means, in covering other metals with copper, he can produce any variety of 
colour that may be desired. The most important applications of the discovery 
are the deposition of copper and the bronzing of iron and steel without the 
preparatory dressings -with conducting substances, vdiicli are necessary when 
the deposit is produced by means of galvanic agency. M. Well considers 
that by his process iron and steel may be first coated with copper, and after- 
wards covered with a stratum of silver or nickel. 
Aniline Blade, which is a new member of the aniline series, differs in 
many particulars from all other black colouring materials. It is easily fixed, 
has a powerful attraction for fabrics, and does not appear to be affected by 
either physical or chemical agencies. Mr. Lightfoot’s process for the pre- 
paration of this dye has been abeady described. ' A new method, however, 
has been announced by M. Lauth. This, which is a modification of Mr. Light- 
foot’s invention, consists in printing with a sulphide of copper in addition to 
the hydrochlorate of aniline and chlorate of potassium. Sulphide of copper, 
though an insoluble salt, becomes oxidized, and soluble on the fabric. By 
the oxidizing action of the chlorate the sulphide becomes sulphate, and by 
the action of this the desired result is obtained. — Vide Moniteur Scientiiique, 
January, 1865. 
GEOLOGY AND PALEONTOLOGY. 
Distribution of the Laurentian Bodes. — This subject is discussed by Sir 
Koderick Murchison in a paper, in which he shows that the relation now 
believed to exist between certain beds in Scotland and Ireland and the 
Laurentian system as it is developed in Camada, was pointed out by him 
years ago. The British rocks which he has shovrn to be of Laurentian age 
occupy striking headlands in Sutherland and Boss, where they are un- 
conformably surmounted by both Cambrian and lower Silurian rocks. At 
first he gave them the name of “Fundamental Gneiss.” They were then 
described as being completely dissevered from aU the palaeozoic rocks, not 
only by unconformability, but also by having a peculiar divergent strike 
from S.E. to N.W., being at right angles to that of all the superjacent 
deposits of Britain. It appears that, although Sir Roderick fancied the 
system described by him was related to the Laurentian, he was unaware of 
the identity of the two till he called the attention of Professor Ramsay to the 
striking features of the “Fundamental Gneiss.” The Professor, however, 
who had explored the Canadian rocks in company v/ith Sir W. Logan, at 
once declared Sir Roderick’s new system to be genuine Laurentian. Atten- 
tion is now called to the matter by the author of “ Siluria ” because of the 
circumstance that Sir Charles Lyell, in the edition of his “ Elements ” just 
published, does not allude to Sir Roderick Murchison’s discovery, but 
dismisses the subject of Laurentian rocks in the following words : — “ The 
