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POPULAR SCIENCE REVIEW. 
substance as manure. — Vide The Dublin Quarterly Journal of Science^ 
No. XVI. 
Verdict against the Nitrogen Theory. — A writer in one of the American 
scientific journals, in reviewing the various discussions which have, during 
the last ten years, taken place in this country between Liebig on the one 
hand, and Messrs Lawes and Gilbert on the other, brings in a clear and 
decided verdict in favour of the former. Adopting the expression cinereal^ 
instead of mineral or inorganic, to embrace all the elements found in the 
ashes of plants, he observes, “ the ‘ good substitute ’ for cinereals, put forth 
in 1851, has had a fair trial, and has failed. Ammonia, judged by the 
experiments of its advocates (as well as by many other trials), proves not to 
be, as was alleged, a ‘ specific ’ manure for corn. The ‘ specific ’ value of 
potash and the phosphates for leguminous and root crops respectively, stands 
equally disproved. Corn and meat cannot be continuously exported from 
soils for 6,000, 2,000, or 1,000 years without restitution (respectively) of the 
silica potash and phosphates removed in their tissues from the soils. These 
illusory views, which their advocates (to do them justice) have already, to a 
large extent, honourably renounced, must be utterly abandoned. The 
celebrated nitrogen theory is at an end, and vdth it falls also the doctrine of 
‘ manurial specifics.’ We now know that the costliest ammonial .salt, and the 
cheapest and commonest of the cinereals (say, for example, silica or lime), 
judged by the spongiole of a plant’s root, are of precisely equal value : each 
priceless so far as essential to the plant’s nutrition, each worthless as to eveiy 
molecule beyond.” — Vide The Canadian Naturalist and Geologist^ new 
series, vol. i.. No. III. 
How to use Sewage Matter. — An eminent authority has lately written a 
pamphlet to show that should the sewage matter be allowed to accumulate 
and be then distributed by canals of irrigation, considerable danger to the 
health of the population must arise. He recommends that means should be 
adopted to clarify the sewage liquid and retain the sedimentary matter, so 
as to form a portable dry manure. This view he supports with very 
powerful arguments, and with a degree of logical acumen not very often found 
in semi-scientific pamphlets, and urges upon the Metropolitan Board of 
Works for its adoption. — -Vide The Utilization of Sewage. By I. Alex. 
Manning, of the Inner Temple. London : Hatchard. 
ASTEONOMY. 
Changes in the Lunar Surface. — Mr. Webb gives some curious observations 
respecting the discrepancies which he remarks in Beer and Maedler’s map of 
the moon, and is afraid that, although the position of the mountains is ac- 
curately given, the details depending on the eye-measurements and sketches 
are not equally trustworthy. In a work of such magnitude this is scarcely 
to be expected, and corrections must be made, from time to time, by those 
who possess better instruments and concentrate their attention on one par- 
ticular district. Mr. Birt finds that the greatest deficiencies occur at the 
edges of the moon, where, from the crowded position of the mountains pro- 
duced by the foreshortening, they are most likely to be found. It is clear, 
