Final answer:
The impression White is conveying about the lake is one of nostalgia, with language and imagery that evoke serene reflection and longing for the past.
Step-by-step explanation:
The central impression that White is trying to convey about the lake, based on the first two paragraphs provided, is one of nostalgia. The language and imagery used in the paragraphs evoke a sense of serene reflection and a longing for the past. The descriptions of the lake shedding its mist in the morning, the serene water during a gentle rain, and the overall stillness and reflection deeply intertwined with nature paint a picture of a place that is cherished and carries personal significance. The use of phrases like "dreaming or was what I saw by the lake truly there", referring to the mist as "ghosts", and the mention of a "nocturnal conventicle" add to this impression, suggesting a deep personal connection and a reflection on past experiences.