Item,~ and Noveltie.~. 153 decay of these materials as displayed in many English cities. The obvious inference as to its cause being that it was due to the action of the acids absorbed in the rain-water, the author was led to test the behavior of a number of samples towards acids, with the following results : Blocks of various stones, of the size of one cubic inch, were broker, by permitting a hammer to fall upon them from a given distance, and recording the number of blows required to produce

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... i-aetion. The same material was next steeped for awhile in diluted sulphuric acid, and subjected then to the same test; the result being that some of the specimens gave way at once, while others withstood the test with varying degrees of deterioration from the original quality. These experiments are only the beginning of a series on the subject, and they promise to furnish quite a valuable contribution to our knowledge.