Microwave spectra of the ground and first excited vibrational states of the normal and amine deuterated species of 3-aminopyridine and 4aminopyridine have been assigned and the structure of the amine group has been determined in these two molecules. The structure of the amine group in the aminopyridines has been derived from ab initio molecular orbital calculations using single determinant molecular orbital wave functions constructed from standard minimal basis sets of contracted Gaussian orbitals. The experimental and theoretical results are found to be in broad agreement with each other.

A clayey solifluction deposit of Devensian age on the lower slopes of a broad valley in Namurian mudstone is about 1.2 m thick and near its base are shear surfaces, gently undulating and occupying on average 40% of the length (56 m) examined in trial pits. Within a shear zone up to 2 mm in thickness the clay mineral aggregates are aligned sub-parallel to the shear surface; otherwise the aggregates are in random orientation. Tests show that strength on the shear surface falls to the residual value (c′ = 0, φr′ = 12°) after small displacements. The resultant peak strength parameters of the deposit, allowing for the undulating and discontinuous nature of the shears, are c′ = 6 kPa and φ′ = 18°; as compared to c′ = 10 kPa and φ′ = 20° for the intact clay. Average index properties are w = 40, LL = 75, PL = 32 and clay fraction = 62%.

In the twelve years since the paint load test was introduced, much experience has been gained in its use. This paper reviews published papers reporting constructive criticism of test procedures and case histories.

BS 5930 proposes fundamental changes to current practice in the description of soils and rocks. The paper reviews these changes and suggests alternative proposals which provide a workable reconciliation between the aims of the new Code and current practical soil and rock description. The main changes made by the Code and the authors' recommendations are:The distinction between fine soil and coarse soil solely on grading is rejected in favour of description according to engineering behaviour.The distinction between silt and clay solely on the basis of the A-line is supplemented with additional terms for borderline cases.Simplification and extension of terminology for description of secondary constituents of mixed soils.Rejection of proposed weathering classification for rocks as inapplicable, in favour of current practice.Clarification of rock nomenclature to conform with geological conventions.The changes to current practice made by BS 5930 are considered to be a retrograde step and could lead to confusion and errors. The paper also considers the process of sample description and attempts to clarify the definition of terms employed in fracture logging of rock core.The paper calls for a revision and reissue of Section 8 of the new Code.

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