254 



SCIENCE. 



[Vol. XX. No. 509 



A large number of bacteria possess this power of producing 

 rennet, though not more than nine or ten have thus far been ex- 

 perimented upon. Those studied differ much in the amount of 

 the ferment produced, some giving large quantities, and others 

 only traces. Thus far it seems that all species of bacteria which 

 liquefy gelatin produce this rennet ferment, although some of 

 them only in small amount. 



This general line of vpork is thus leading bacteriologists to a 

 better understanding of the fermentations, although we are as yet 

 doubtless far from any real knowledge of their nature. 



IS THE SAO FRANCISCO DO SUL (SANTA CATHARINA) 

 IRON A METEORITE? 



BT ORVILLE A. DERBY, SAO PAULO, BRAZIL. 



The possibility of a terrestrial origin for masses of native iron 

 being established by the well-known occui-rence at Ovifak, Green- 

 land, doubt may be cast on the mode of origin of such so-called 

 meteorites as in their chemical and physical characters depart 

 widely from the ordinary type of meteoric iron. From its size 

 and prominence in meteoric literature the most important exam- 

 ple of such a doubtful iron is that found in 1875 near the 

 city of Sao Francisco do Sul, in the State of Santa Catharina, 

 Brazil, and generally known as the Santa Catharina iron or me- 

 teorite. Professors Daubree and Stanislas Meunier regard it as 

 undoubtedly meteoric; while Dr. A. Brezina, whose opinion is 

 equally entitled to respect, considers it as probably terrestrial, 

 placing it alongside of the Ovifak iron in his catalogue of the 

 Vienna collection. 



So far as known to the writer, no such minute study as Brezina, 

 Cohen, and others have given to various undoubted meteorites 

 lias as yet been made of the Ovifak iron, so that at present we 

 are in the dark as to whether or not it presents definite criteria by 

 which a terrestrial iron can be positively separated from a me- 

 teoric one. So many of the characteristics once presumed to be 

 purely meteoric have already been noticed, either in the Ovifak 

 or artificial irons, that it may be doubted if any such definite cri- 

 teria exist. The published analyses of Ovifak show that neither 

 the nickel-iron alloys nor the association with a monosulphide 

 (troilite) carbon free or combined and phosphorus can be taken 

 as distinctive of meteorites. It is not clear, however, if the car- 

 bon presents the same form as in meteorites, that is to say, fi'ee 

 in the form of amorphous carbon, graphite, cliftonite, dia- 

 mond (?), etc., and combined as cohenite, nor if the phosphorus 

 is combined with iron and nickel as in the meteoric minerals 

 schreibersite and rhabdite. On the other hand, the compact 

 (Dichte Eisen) group of Brezina containing at least nine undoubted 

 meteorites, one of which, NedagoUa, was seen to fall, proves that the 

 absence of a certain crystalline structure, indicated by the so- 

 called Widmanstatten and Neumann figures, is not necessarily 

 proof of non-meteoric origin. On the contrary, evidence is accu- 

 mulating that a very similar if not absolutely identical crystalline 

 structure may, under favorable circumstances, appear in artificial 

 irons. Huntington has illustrated figures very like those of 

 Widmanstatten in spiegel-eisen ; Linck has described a crystal 

 from a furnace slag, with cube faces and a polysynthetic twin- 

 ning structure, which he identifies with the Neumann figures, and 

 a perfect octahedral crystal with a similar twinning structure has 

 recently come into the possession of the writer from a Brazilian 

 blast-furnace. 



It may be presumed that it is mainly on the absence of the 

 characteristic meteoric figures that Brezina depends in placing 

 the Sao Francisco do Sul with the Ovifak iron, as in no other re- 

 spect are they markedly similar. The Brazilian iron does, how- 

 ever, show, at least in places, a very fine rectilinear cross-hatch- 

 ing indicative of polsynthetic twinning, but according to some 

 law different from that giving the Neumann lines. Another 

 point of agreement is in the abundant occurrence of the magnetic 

 oxide of iron which is either absent from most meteorites or has 

 been overlooked in their description. Both irons are brittle, 

 being readily broken to fragments with a hammer, in which re- 



spect they differ from the tenaceous malleable metal of most 

 meteorites. Both also crumble to fragments in the atmosphere 

 of museums, though apparently not from the same cause, the 

 crumbling of Sao Francisco do Sul being due to alteration of the 

 sulphide, which presumably is not the case with Ovifak. 



Lawrence Smith and Becherel found the magnetism of the 

 Brazilian metal abnormally weak but that it became normal on 

 heating, from which they concluded that the mass could not 

 have been subjected to great heat. There seems, however, to be a 

 variation in this respect in different parts, since Daubree notes 

 that many fragments exhibit polar magnetism while others do 

 not. Any argument drawn from the magnetic properties would 

 apparently tell as much against a terrestrial as a cosmic origin, 

 since the only conceivable mode of terrestrial origin is in the 

 midst of an igneous magma made fluid by heat. 



In other respects, however, a parallel for the characteristic fea- 

 tures of the Sao Francisco do Sul iron is to be looked for in the 

 group of meteoric irons rather than in those, so far as published, 

 of the terrestrial iron of Ovifak. It is particularly characterized 

 by the high percentage of nickel and the extraordinary abundance 

 of sulphide. In the first respect its nearest ally is the Oktibbeha 

 meteorite with nearly double the proportion of nickel, and not 

 the Ovifak iron in which that metal is below the meteoric average. 

 Unlike any other known iron, meteoric or terrestrial, the sulphide 

 forms a gangue inclosing the metallic parts, but it is interesting 

 to notice that it also presents itself in pencil-like inclusions in the 

 metal, surrounded by carbon and other accessories, as in the Ben- 

 dego meteorite. The meteoric phosphurets, schreibersite and 

 rhabdite, not yet described from, though perhaps present in, the 

 Ovifak iron, are abundant accessories. In the carbonaceous resi- 

 due, soft, friable granules, with a crystalline form suggestive of 

 the cliftonite of the Youngedin, Magura, and Bendego meteorites, 

 have been noticed. 



Thus, so far as at present known, the chemical and physical 

 characteristics of the Sao Francisco do Sul iron do not point very 

 markedly to an association with that of Ovifak. What is known 

 of the geological conditions of the place of discovery, although 

 too incomplete to be decisive, points rather to a meteoric origin. 



The geological information regarding the place of discovery is 

 derived from verbal communications by the late Professor Ch. 

 Fred. Hartt, a paper in the Revista do Observatorio de Rio de 

 Janeiro for 1888 by Dr. Luiz F. Gonzaga de Campos, and a recent 

 article in the Jornal do Commercio of Rio, May 29, 1892, by Dr. 

 J. P. Calogeras. All these accounts agree in representing the 

 island of Sao Francisco do Sul as composed essentially of grani- 

 toid gneiss cut by dykes of tournjaline granite and diabase and 

 covered by a heavily-wooded soil-cap due to the decay of the 

 underlying rocks. That is to say, it is a typical locality of the 

 coast-belt from Cape Frio to Montevideo, at any point of which, 

 so far as geological indications go, native iron might be looked for 

 with as great probability as at this particular locality. The 

 rocks, granite, gneiss, and diabase, are well exposed about the 

 shores of the island. The latter, which approaches most nearly 

 in character the Ovifak rock, being apparently no more abundant 

 than in any other similar locality. In the interior of the island 

 the soil-cap and forest growth make geological observations dif- 

 ficult. Dr. Campos, in his examination of the place of discovery 

 of the iron, opened numerous paths and pits, and on my recom- 

 mendation paid particular attention to the question of the possible 

 occurrence of basic rocks in immediate connection with the iron. 

 He says, " Although the rock on this hillside is much altered, 

 giving an argillaceous soO of a red color, here more, there less 

 deep in tint, it shows perfectly in some points the mineral com- 

 position of granite. At the top of the hill near the point c [one 

 of the points where masses of iron were found] there are large 

 blocks of granite, at times tourmaliniferous. In the vicinity, in 

 all the directions that I followed, all the soil is granitic. In the 

 bed of the stream, which I ascended in various sections, the ma- 

 terial was always that of the disaggregation of granitoid gneiss. 

 Finally, I did not find at this place a single exposure of basic 

 rock." The numerous specimens that have come to hand show- 

 ing foreign material cemented to the iron by the limonite crust 

 formed by its alteration are in accord with this description, indi- 



