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POPULAR SCIENCE REVIEW'. 
river systems, and the correlation of the Cambridgeshire drifts with those of 
the eastern counties. 
In conclusion Mr. Jukes-Browne offers a few remarks on the conditions 
under which the glacial deposits have been formed, and the age of the prin- 
cipal features of the country — questions which have been much contested, 
and certain opinions connected with which he briefly criticizes, and explains 
his own views upon them. 
Without, however, attempting to give a history of the manner in which 
Cambridgeshire was moulded, the author gives his views as to the relative 
age of its principal physical features from the evidence he has brought for- 
ward, and states that “the whole succession of post-glacial valley gravels 
seems indeed to have been singularly well preserved in this part of England, 
and if the various beds could be thoroughly disentangled, they would mark 
out the courses of the streams at different times, and present us with a 
picture of the successive changes which have taken place in the river system 
from the glacial period to the present time.” 
To the student of Post-Tertiary Geology this will be an acceptable essay, 
as the descriptions are given in a clear and systematic manner, embodying 
not only the author’s own researches, but those of other geologists who have 
specially studied these deposits. 
THE ELECTRIC LIGHT.* 
T HIS is an enlarged issue of the pamphlet by Mr. Shoolbred, already 
noticed in the two articles upon the Electric Light in our numbers for 
January and April. It contains a fair description of the various dynamo- 
electric machines lately invented; and, although Mr. Chapman’s gravity 
lamp, which by many years preceded similar recent contrivances, and 
quite equalled them in performance at the recent exhibition in the Albert 
Hall, is still excluded, those now before the public are illustrated and 
explained. The plates are on a good scale, and easy to understand. Mr. 
Shoolbred is evidently a thorough and uncompromising advocate of this 
mode of illumination ; so that any adverse facts or opinions must be sought 
for elsewhere. 
THE HEAVENS, t 
“ Spake full well, in language quaint and olden, 
One who dwelleth by the castled Rhine ; 
When he called the flowers so blue and golden, 
Stars, that in Earth’s firmament do shine.” 
"jV/TR. PROCTOR might well have added the above verses of Longfellow 
■HE to the stanza of Shelley which adorns his prefatory page. They would 
complete the simile which evidently underlies his quaint and fanciful title. 
* “ Electric Lighting and its Practical Application, with Results from 
Existing Examples.” By J. N. Shoolbred, B.A., &c. 8vo. London : 
Ilardwicke & Bogue, 1879. 
t “The Flowers of the Sky.” By R. A. Proctor, & c., &c. With fifty- 
four Illustrations. 8vo. London : Strahan & Co., 1879 
