58 



SCIENCE. 



[Vol. IX., No. 207 



bedding, or nearly so. Besides quartz and tourma- 

 line, they carry iron and titanium minerals (magne- 

 tite, hematite, rutile, and anatase), amorphous 

 chloro-phosphates of some of the rarer elements 

 (cerium, lanthanum, didymium, etc.), and, almost 

 certainly, euclase. 



The observations at this place exclude completely 

 the idea of peridotite or other eruptive rocks. The 

 diamond at Sao Joao da Chapada, and presumably at 

 other Brazilian localities, is a vein mineral, and the 

 conditions of its genesis (unless we admit the hypoth- 

 esis of a subsequent deposition of carbon, which is 

 uncalled for by any of the observations thus far 

 made) must have been such as were favorable to the 

 segregation of iron and titanium oxides, phosphates 

 of rare elements, and certain silicates, such as tour- 

 maline and presumably topaz and euclase. The 

 hypothesis of a genesis through the reaction of erup- 

 tive masses on carbonaceous schists is here as inad- 

 missible as would be that of a vein formation for the 

 South African mines. If the origin of the carbon is 

 to be sought in the rocks traversed by the eruptive 

 or vein masses containing it, it is not without 

 interest to mention that the schists of the veins 

 in which the Sao Joao mine is excavated frequently 

 contain graphite, though at that particular locality 

 they are too much decomposed to enable one to 

 determine whether it occurs there or not. It may be 

 stated, that, in the other diamantiferous regions of 

 Bahia, group 2 occurs either at the mines or in suffi- 

 cient proximity to have furnished the diamonds. 

 In the Bahia fields the precious stones appear to 

 have come mainly from a conglomerate which, as it 

 lies in the prolongation of the same range, is pre- 

 sumably identical with group 3 above described, and, 

 like it, rests on a base of unctuous schists, itacolumite 

 and itabirite. The Goyaz fields and those of Bagagen 

 in western Minas seem to be similar to those of 

 Diamantina, though perhaps lacking the upper 

 quartzite. To the west of Diamantina, in the San 

 Francisco valley, diamonds are washed from the 

 dibris of a conglomerate presumably of upper 

 Silurian or Devonian age, but containing pebbles 

 of the Diamantina rocks. In the province of Parand 

 the immediate origin is in a Devonian conglomerate, 

 and this is also apparently the case with the diaman- 

 tiferous placers of the province of Matto Grosso. 



The Brazilian and African diamond-fields thus in- 

 dicate two very distinct modes of occurrence and 

 genesis for the gem, — one as a vein mineral accom- 

 panying oxides, silicates, and phosphates ; the other 

 as an accessory element in an eruptive rock. In the 

 last number of the Bulletin de la SociHS g^ologigue 

 de France, M. Chaper presents a third mode of oc- 

 currence as the result of his observations in an 

 Indian diamond-field. He satisfied himself that the 

 gem occurs there, along with sapphires and rabies, 

 in a decomposed pegmatite, having taken out two 

 diamonds, two sapphires, and three rubies from an 

 excavation made in that material. The circumstance 

 that all these stones were found during the prelimi- 

 nary work with pick and shovel, whereas nothing was 

 found in the washing, would, notwithstanding M. 

 Ohaper's confidence that no deception was prac- 

 tised, seem to the practical diamond-miner to 

 be extremely suggestive of salting very in- 

 artistically done. The occurrence of remnants 

 of a sedimentai-y formation of a conglomeritic 

 character in the neighborhood of the old washing 

 examined suggests another explanation for the occur- 



rence of the gem in placers resting on a bottom of 

 granitic rocks. Obville A. Derby. 



Museum nacional, Rio de Janeiro, 

 Dec. 16. 



A German sentence. 



Will you allow me a brief reference to a remark of 

 one of your contributors ? ' M.' quotes the follow- 

 ing German sentence by ' one of the most distin- 

 guished German zoologists : ' — 



" Man darf fiir wahrscheinlich halten, dass die so 

 sehr wechselnde Gestalt und Ausbildung der ' Tast- 

 borsten,' nach der Art des Thieres und den Korper- 

 gegenden, noch bestimmten Nebenzwecken zu dienen 

 hat, ohne dass wir uns davon Bechenschaft zu geben 

 vermogen." 



In the original quotation the commas after ' Tast- 

 borsten ' and before 'noch,' etc., are omitted. ' M.' 

 quotes this as a sample of sentences which prove 

 that German scientific writers despise the ' French 

 qualities of grace and lucidity.' 



He goes further than this. He is quite convinced 

 that the scientific men in Germany show an ' absence 

 of the literary sense,' though he admits there axe 

 some exceptions. 



It seems to me that if ' M.' wished to furnish a 

 proof for his assertion, he ought to have chosen a 

 different sentence. Evidently every thing depends 

 upon the reader for whom the sentence was intended. 

 If the author vsTrote for children, his sentence was 

 objectionable ; but, if he wrote for educated persons, 

 the sentence must be pronounced just as clear, lucid, 

 and elegant in German as any similar sentence might 

 be in French. ' M.' assumes to judge of the literary 

 qualifications of people who use a language with 

 which he himself is less familiar than he is with 

 French and English; a language, moreover, which 

 greatly differs in its laws of construction from French 

 and English. Supposing he should apply his French 

 or English standard to a similar Latin sentence by 

 one of the recognized masters of Latin style, would 

 the difficulty of understanding its meaning justify a 

 person who is not perfectly at home in that language 

 to condemn the form of the sentence ? 



It seems to me ' M.'s ' reasoning is the reverse of 

 ' scientific' It looks very much like ' jumping at 

 conclusions.' ' M.' goes further than this. He re- 

 marks on the lack of German inventiveness But do 

 the Germans lack inventors? They are inferior to 

 the Americans in invention of labor-saving machinery, 

 because they have not hitherto felt the need of it as 

 much as Americans in their thinly peopled country. 



But let us ask who invented watches, lithography, 

 the original hand-press for printing, and the later 

 revolving press, for the first time used in printing 

 the London Times, which created a new era in news- 

 paper printing ? Who has a greater claim to the in- 

 vention of the electric telegraph than Gauss of 

 Gottingen, or Steinheil of Munchen ? Where are 

 there more practical inventors than Krupp and the 

 men that have made his steel- works famous all over 

 the world ? And how about Siemens (the two elder 

 brothers), Halske, Schaefer, Budenberg, Gruson, 

 and scores of others ? Germany, so long disunited, 

 could not afford a patent law like our own until 

 quite recently : hence many of her inventors went 

 to England, France, and some to this country. 



There is some truth in ' M.'s' remark about the bad 

 style of many German scientific writers, but I ven- 

 ture the assertion that the number of really fine 



