METEORIC AND ARTIFICIAL NICKEL-IRON ALLOYS. 
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treatment upon the density of the material. § 13. Hypothetical account 
of the process of crystallisation in meteoric iron. § 14. Effect of change in 
rate of cooling. § 15. Comparison with experimental data. § 16. Effects 
of prolonged heating upon the structure of meteoric iron. 
VIII. Further data from artificial alloys.104 
§ 1. The beginning of magnetic crystallisation in nickel-iron alloys. § 2. The 
evidence of the existence of a eutectic in the nickel-iron series. § 3. The 
experiments of Honda and Shimizu. § 4. The possibility of detecting the 
co-existence of different nickel-iron alloys in the same material. § 5. Inter¬ 
pretation of the properties of an alloy containing 36 per cent. Ni. 
§ 6. Alloys containing between 30 and 28 per cent. Ni. § 7. The alloy 
containing about 27 per cent. Ni. A “ magnetic invar.” § 8. Alloys 
containing about 24 per cent. Ni. § 9. The thermomagnetic properties of 
the eutectic of artificial alloys. § 10. The value of further thermomagnetic 
examination of other alloys. §11. Further data with respect to the 
meteoric iron. § 12. Conclusion. 
Section I.— Description of the Materials of which the Thermomagnetic 
Properties were Investigated. 
§ 1. The experiments described in this paper arose from the desire of Sir Arthur 
W. Pucker to obtain, in connection with his researches on the nature of the Earth’s 
magnetic field, further data concerning the properties of such magnetic materials of 
natural origin as may be present in appreciable quantity in the Earth’s crust. 
Iron of cosmic origin contains nearly always an appreciable quantity of nickel, and 
the magnetic properties of this material, especially their variation with temperature, 
have received very little attention. Most of the published data are qualitative only, 
and from them no very definite conclusion can be drawn beyond the fact that meteoric 
iron appears - to be of very variable permeability. It was, therefore, thought desirable 
to make a careful quantitative study of a typical example of such material. 
§ 2. The meteoric iron used in the experiments was bought from the firm of 
Dr. A. E. Foote, and the mass from which the sample was cut is described bv 
A. E. Foote in the ‘American Journal of Science’ [4], vol. 3, p. 65, 1897. The 
whole meteorite weighed about 237 kilogs. and was found in the Sacramento 
Mountains, Eddy Co., New r Mexico. A careful analysis of some fragments yielded 
the results :— 
Fe = 9D39 
Ni = 7-86 
Co = 0-52 
99-77 
