234 



SCIENCE 



[N. S. Vol. XXVIII. No. 712 



whicli Mr. KJraus bases a second argument, is 

 to my mind of no significance. The beni- 

 toite and the natrolite matrix in which it 

 occurs are clearly secondary and must have 

 been formed from percolating solutions. Even 

 if it be assumed that these solutions were also 

 basic it by no means follows that the titanium 

 which they contained would take the part of a 

 base, on the contrary it is more probable that 

 ii would take the part of an acid. Associated 

 with the benitoite are two other titanium- 

 containing minerals, namely, titanite and a 

 mineral to which the name carlosite was 

 given, but which we have since shown to be 

 identical with neptunite. All three minerals 

 are found in the natrolite matrix and appear 

 to have been formed contemporaneously. 

 There is good reason for supposing that 

 titanium takes the part of a base in both 

 titanite and neptunite and it is not probable 

 that a third mineral formed under similar 

 conditions would differ in this respect. 



There is on the contrary much to be said 

 in favor of the formula suggested by Mr. 

 Louderback. The properties of the element 

 titanium, when in this degree of oxidation, 

 are clearly those of a very weak acid. The 

 entire lack of a definite compound of titanium 

 and silicon, in view of the frequent occurrence 

 of both oxides in the same formation, is 

 striking. If benitoite is a double metasilicate 

 of barium and titanium it is most remarkable 

 that the proper conditions for the formation 

 of both its constituent single salts have no- 

 where prevailed. 



A cursory examination of the literature 

 shows that many of the compounds in which 

 titanium is supposed to take the part of a 

 base have not been isolated in pure form, nor 

 has their structural formula been satisfac- 

 torily determined. They are in all proba- 

 bility analogous to certain complex acids, such 

 as those which phosphoric acid forms with the 

 acids of the chromium group of elements 

 rather than to simple salts. 



Titanium is more closely related to silicon 

 than to the more basic zirconium. Like the 

 former element it shows a decided tendency 

 to combine with itself and form complex 



molecules, and the substitution of one element 

 for the other in such a chain would not seem 

 unreasonable. Further, there is nothing un- 

 reasonable in the formation of compounds 

 containing such a relatively large percentage 

 of acidic elements if the acidic elements rep- 

 resented are very weak in their properties and 

 the basic elements are very strong in theirs; 

 the compound borax furnishes a good illus- 

 tration. W. 0. Blasdale 

 Depaktment op Chemistkt, 

 Univeesitt op Cat.tfobnia 



appointments in american unwersities 

 To the Editor of Science: As a Scot, called 

 some years ago to teach in an American uni- 

 versity, I am much interested in Dr. S. J. 

 Meltzer's communication, printed in Science 

 of AugTist 7, especially as two of the gentle- 

 men to whom he refers are countrymen of my 

 own. However, my purpose is not to traverse 

 his protest, which seems to me well taken. 

 Dr. Meltzer's letter involves a much larger 

 question. I think that those of us who have 

 to make recommendations for vacancies must 

 have felt often that here, at least, we stand 

 badly in need of a clearing-house. Wby 

 should not each great department of inquiry 

 have its own bureau of information, to bring 

 men and places together? Our present 

 methods are largely haphazard, especially with 

 reference to the less important appointments, 

 whence the more important must be filled some 

 day. One hears of vacancies after they have 

 been settled; and one's knowledge of available 

 appointees, especially of the younger men, is 

 far from complete. Here is an opportunity 

 for Science and similar publications to venti- 

 late a need, with a view to common action. 

 E. M. Wenley 

 Univeksity op Michigan 



SCIENTIFIC BOOKS 

 Musee Osteologique. Etude de la Faune 

 Quaternaire. Osteometrie des Mammiferes. 

 Par Edmond Hue Medecin Veterinaire, 

 Membre de la Societe Prehistorique de 

 France. Album de 186 planches contenant 

 vi + 50, pi. 93. Deuxieme Fascicule, pi. 

 2,187 figures. Premier Fascicule, pp. 



