204 PROGRESS OF MICROSCOPICAL SCIENCE. ["o" mL'i. ?\p 'ilt'lsTi?.' 



TIcC Structure of Steel as seen hi/ the Microscope.— In a note pub- 

 lished ill ' Scientific Opinion ' of March 2ncl, a record of some of M. 

 Schott's (of Ilsenberg) recent researches in the crystals of iron and 

 steel is given. BI. Schott maintains that all crystals of iron are of 

 the form of a double pyramid, the axis of which is variable, as com- 

 pared with the base. The crystals of the coarser kinds, as compared 

 with those of the finest qualities of crystalline iron, are of about 

 twice the height. The more uniform the grain, the smaller the 

 crystals, and the flatter the pyramids which form each single element, 

 the better is the quality, the greater is the cohesive force, and the finer 

 the sm-face of the ii-on. These pyi-amids become flatter as the pro- 

 portion of carbon contained in the steel decreases. Consequently in 

 cast iron and in the crudest kinds of hard steel the crystals approach 

 more the cubical form, from which the octahedron proper is derived, 

 and the opposite extreme or wrought iron has its pyramids flattened 

 down to parallel surfaces or leaves, which in their arrangement 

 produce what is called the fibre of the iron. The highest quality of 

 steel has all its crystals in parallel positions, each crystal filling the 

 interstices formed by the angular sides of its neighbours. The 

 crystals stand with their axes in the direction of the pressure or per- 

 cussive force exerted uj)on them in working. 



The Structure of Eozoon. — Professors Eowney and King, of Queen's 

 College, Galway, still dispute the view propounded by Dr. Carpenter, 

 and now generally accepted among biologists, that the Eozoon 

 structiu'e is the fossil relic of some protozoan animal. At a meeting 

 of the Eoyal Irish Academy held last month, the Secretary read a 

 note by Professors King and Eowney, of Galway, supplementary to a 

 former paper on " Eozoon Canadeiise." " The note," say the authors, 

 " is descriptive of two specimens, one from Aker, Sweden, and the 

 other from Amity, New York. The Aker specimen is a crypto- 

 crystalline mass of calcite, enclosing numerous lobulated gi'ains of 

 coccolite, respectively identified with the ' supplementary skeleton ' 

 and ' chamber casts ' of this reputed organism in its ' acervuline ' 

 form. Their presumed organic origin, however, is clearly a fallacy, 

 as the grains of coccolite display unmistakable evidences of having 

 been originally crystals that have had their edges, solid angles, and 

 faces, more or less rounded off by some dissolving agent. Imbedded 

 in the calcite are numerous long crystals of what appears to be 

 raalacolite, lying about singly and in aggregations. In most instances 

 the crystals have lost some or all of their planes, angles, and edges, so 

 that many present themselves under the massive contorted cylindrical 

 forms peculiar to the so-called ' stolons ; ' others, through prismatic 

 cleavage, are broken uj) into slender prisms, which, in numerous 

 instances, are reduced by erosion ; and further division, to simple and 

 branching configurations, assuming all postures and modes of group- 

 ings. The latter match in beauty the finest examples of the ' canal 

 system ' seen in typical ' cozoonal rocks ' occurring in Canada. The 

 Amity specimen consists of a similar calcareous matrix, holding 

 crystals of sjjinel, malacolite, and other minerals. In one of the 

 crystals of spinel, an octahedi-on, about 2^ in. in its axial diameter. 



