458 



Presents. 



[Mar. 21, 



will be seen that the temperature coefficient of iron ranges from 

 0*0048 at the ordinary temperature to 0*018 at a temperature just 

 short of 855 C. ; it then suddenly changes to about 0'0067. The last 

 coefficient can only be regarded as a somewhat rough estimate. 



This temperature being a higher temperature than I had observed 

 previously in any case as the temperature at which a sample of iron 

 ceases to be magnetic, it appeared desirable to ascertain whether the 

 iron wire differed from other samples in this respect. A ring was 

 formed of the wire, and was wound with a 'primary and secondary 

 coil, and the resistance of the secondary was determined when the 

 magnetisability of the iron disappeared. It was found that this 

 resistance was the resistance which corresponded to a temperature of 

 870 C. ; this temperature agrees with that at which the discontinuity 

 in the resistance curve occurs, within the limits of errors of observa- 

 tion. 



Presents, March 21, 1889. 

 Transactions. 



Baltimore : Johns Hopkins University. Circular. No. 69. 4to. 

 Baltimore 1889. The University. 



Munich : Konigl. Bayerische Akademie der Wissenschaften. Ab- 

 handlungen (Philos.-Philol. Classe). Bd. XVIII. Abth. 1. 

 4to. Munchen 1888; Das Bayerische Pracisions-Nivellement. 

 Siebente Mittheilung, von Carl Max v. Bauernfeind. 4sto. Munchen 



1888. The Academy. 

 Naples : Accadeinia delle Scienze Fisiche e Matematiche. Rendi- 



conto. Ser. 2. Vol. II. Fasc. 1-12. 4to. Napoli 1888. 



The Academy. 



New York : American Geographical Society. Bulletin. Vol. XX. 



Supplement. 8vo. New York 1888. The Society. 



Paris : Ecole Normale Superieure. Annales. Annee 1889. No. 2. 



4to. Paris. The School. 



Societe de Geographic. Bulletin. Tome IX. Trim. 4. 8vo. Paris 



1889. The Society. 

 Societe Mathematique de France. Bulletin. Tome XVI. No. 6. 



8vo. Paris 1888. The Society. 



Home: B. Comitato Geologico d'ltalia. Bollettino. Nos. 11 e 12. 



8vo. Roma 1888. The Comitato. 



Toronto: Canadian Institute. Proceedings. Vol. VI. No. 1. 



8vo. Toronto 1888. The Institute. 



Vienna: Anthropologische Gesellschaft. Mittheiluiigen. Bd. 



XVIII. Heft 4. 4to. Wien 1888. The Society. 



Kaiserliche Akademie der Wissenschaften. Anzeiger. Jahrg. 



