[Responding to WT's 1826-2-7], JH thanks WT for materials sent, makes suggestions regarding WT's upcoming trip to Geneva, and asks WT to deliver a book to [Alfred] Gautier.

[Responding to WT's 1826-3-24], JH concurs with P. S. Laplace's view about the advantage of astronomical observation from high elevations, e.g., from mountains. Comments on telescope prices, a paper by WT, Florence, and JH's plan to visit the Continent.

Thanks WT for bringing to JH Josef Fraunhofer's publications and Franz Gruithuisen's plates. Recounts JH's geologizing in France and JH's efforts to measure solar radiation.

Thanks WT for optical equipment sent. Notes death of Augustin Fresnel. Has purchased a telescope from James South.

Responds to WT's 1827-10-29. Sending JH's Light, which uses some of WT's publications.

Asks about a servant JH is considering hiring to accompany JH on JH's trip to the Continent.