Summary This paper, which is an extract from a wider field of investigation of the pressure distribution in a model silo containing different materials, at rest and during flow, describes tests with cement at rest. The results are compared with some of the better-known theories on silos. The main conclusions are that the pressure distribution on the silo base with cement at rest is not uniform hut decreases from the centre outwards, that Janssen's fundamental assumptions when applied to cement are wrong, and that laky's theory over-estimates the load carried by the silo walls whereas, for silos of proportions commonly met in practice, Airy's theory gives quite satisfactory results.