Reactions of the Etherate of Aluminum Triethyl 5193 tetroxide in 1,4-dioxane there is no tendency toward polymerization. In the range up to 0.1 molal, X is equal to unity ±10%. The very slight upward trend at the two higher concentrations reflects the fact that as the concentration of dinitrogen tetroxide increases an appreciable partial pressure of dinitrogen tetroxide above the solution develops. This fact in addition to the general limitations of cryoscopy for molecular weight determinations limited our measurements to dilute solutions.On the basis of the cryoscopic and viscosimetric data reported herein we may conclude that there is little basis for postulating a polymeric, chaintype structure for the compound N204• 1,4-0-(CH2CH2)20.

Magnetic minerals within rocks, meteorites and sediments can record the ambient magnetic field during their formation, acquiring remanent magnetizations. There are several recording mechanisms depending on the rock type and mineral formation. For example, a thermoremanent magnetization (TRM) is acquired during cooling from above the constituent minerals' Curie temperatures, and chemical remanent magnetizations (CRM) are acquired if a mineral forms or alters below its Curie temperature. The recording mechanisms of these various remamances differs. Whilst much attention has historically been given to TRM acquisition (e.g.,

High-temperature susceptibility (HT-χ) data are routinely measured in Earth, planetary, and environmental sciences to rapidly identify the magnetic mineralogy of natural systems. The interpretation of such data can be complicated. Whilst some minerals are relatively unaltered by heating and are easy to identify through their Curie or Néel temperature, other common magnetic phases, e.g., iron sulphides, are very unstable to heating. This makes HT-χ interpretation challenging, especially in multi-mineralogical samples. Here, we report a review of the HT-χ data measured primarily at Imperial College London of common magnetic minerals found in natural samples. We show examples of “near pure” natural samples, in addition to examples of interpretation of multi-phase HT-χ data. We hope that this paper will act be the first reference paper for HT-χ data interpretation.

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We report a new approach of implementing cooling‐rate corrections in absolute ancient magnetic field intensity (paleointensity) studies. Nearly all methods of determining paleointensity estimates rely on rocks having recorded a thermoremanent magnetization (TRM), on cooling from above the rock’s constituent minerals’ Curie temperature. Typically paleointensity estimates are made by comparing natural TRM, with a TRM induced in the laboratory; however, TRM intensity has long been reported to be dependent on cooling rate. Natural cooling rates are impractical in laboratories. We have developed a new cooling‐rate correction method and corresponding software (ThellierCoolPy), that directly corrects the unprocessed paleointensity data, using first‐order reversal curve data collected on a sister sample. This site tailored cooling‐rate correction has a unique correction for each temperature step within the paleointensity data set. This new method differs from previous approaches which apply a blanket cooling‐rate correction independent of the material properties of the sample. Paleointensity data from historical lavas from Parícutin, Mexico, are used to demonstrate the new software. For this data set, it is shown that cooling time of 1 million years yields a reduction of the paleointensity of ∼7%. The software is available for download.