The main idea in this entry from Dorothy Wordsworth's journal is the weather during the writer's journey to Holford, letter B. The entry describes the stormy weather that the writer encountered on their journey, including the sound of the pattering shower and gusts of wind, as well as the clear skies and shining planets that followed. The writer also describes the impact of the weather on the natural environment, such as the black and pointed hawthorn hedges that are "glittering with millions of diamond drops" and the holly bushes that are "shining with broader patches of light." All of these details are focused on the weather and its effects on the surroundings, making it the main idea of the passage.