Polytechnic Association Proceedings. QQ] 



of iron {ferremit) are produced; the remavning ores mentioned are 

 not so rich in iron, being either hydrated sesqui-oxides or car^jouate 

 of iron (fennani). Sixt^^-eight per cent of all the ores used con- 

 tain less than thirtj-five per cent of iron. 



SAPONIN. 



This substance is found in common soap-wort, horse-chestnuts, 

 quillaja bark, corn-cockle, Senega root, pimpernel, and the rbots 

 of pinks. It seems to be widely diffused throughout the vegetable 

 kingdom, and is easily extracted from plants by means of boiling 

 alcohol. Its name is derived from the saponaceous qualities of its 

 solution in water. An infusion of soap-wort is sometimes used for 

 cleansing the finer kinds of wool. Saponin is a nearly white, 

 friable powder, of sweetish taste, and producing a scratching sensa- 

 tion in the throat. Its dust causes violent sneezing, A drop of its 

 solution applied to the eye excites burning pain, and dilates the 

 pupil, Eugene Pelikan, Director of the Civil Medical Department 

 of Russia, lately sent to the Academy of Sciences, Paris, a nota on 

 the local paralysis produced by saponin and analogous substances. 

 The result of his experiments may be briefly summed up as follows: 



1, The local paralysis produced by saponin is followed by a 

 rigidity of the muscles and paralysis of the nerves of sensation. 



2. This local paralyzing action resembles somewhat that of sub- 

 stances acting on the pupil, like atropin, &c. 



3, Saj)oiiin, now employed in medicine, is probably destined to 

 perform another part than that at present attributed to it, and for 

 this reason it should be submitted to new clinical experiments. 



4. Saponin does not cause either contractions of the muscles or 

 other parts to which it is applied, yet it annuls completely the 

 irritability of the muscles, provided the animal submitted to its 

 action is in the normal state of health. 



AMERICAN CONCRETE BUILDING STONE. 



Recent improvements in the manufacture of concrete building 

 blocks have so far perfected the product as to bring this stone into 

 successful competition with the very best of the natural and artifi- 

 cial building materials. The action of lime upon silica, forming a 

 silicate of lime (calanaMt), and thus binding together particles of 

 sand, as in mortar, has been known from the remotest ages, and 

 concrete walls of great antiquity are now standing, vieing with the 

 natural rock in hardness and durability. Some years since a con- 

 crete block, compacted by pressure, was brought out in this country 



