Has read WT's paper before the R.S.L. and now complains they will not print it in the R.S.P.T. as they understand it has appeared elsewhere.

Explains the operation of the Council of the R.S.L. and hopes that WT will treat their unintended slight as a 'gaucherie'.

Expresses reservations about Samuel Brown's work. Apologizes for delay in trying calotype; has done only some vegetable substance trials.

Reports on paper by Samuel Brown to the Royal Society of Edinburgh on the conversion of carbon to silicon, and other transmutations. Reports on discovery of new element, ozone, and complains further about R.S.L. Council.

Sends JH samples of his calotypes. Off to Germany on a photographic expedition.

Thanks for calotypes involving persons engaged in actions. Gives encouragement to WT's planned photographic tour in Germany. JH has been experimenting regarding color photography.

Carl Steinheil has proposed making telescope mirrors by plating silver on glass. Is writing to JH to tell him that somewhat earlier he had included this process in one of his patents.

JH's account of a comet reminds WT of a strange sighting many years ago. Comments further on improvements in photography, both those made and those needed.

Describes observing of comet that evening.

Comments on confusion between observing comet and zodiacal light. Extensive comments on various materials used in a photographic process where negatives change to positives over long time.

Suggests 'amphitype' as name for JH's process whereby same picture can go from negative to positive. Further comments on comet sighting, and on some improvements to Daguerreotype.

Zodiacal light is a real phenomenon. Further comments on negative to positive process. Questions whether WT can define one cometary orbit with two observations.

Comments on JH's positive calotype. Suggests comet may be return of (J.-D.) Cassini's comet of 1668. Gives theorem for finding parabolic orbit of comet if two observations are made in the ecliptic.

Some comments and questions on mathematics.

Comments and questions about a 'cone of the second order' in mathematics.

Grateful for receipt of JH's Cape Results. Sending photographs by several artists to show that 'knowledge of the art is spreading.'

Thanks for excellent Talbotypes. Notes how few photographs are 'perspective representations on a vertical plane' and suggests how to correct this.

Comments on astronomical symbols, and position of camera when photographing buildings.

Has performed experiments measuring the deviation of spectra through an obliquely placed diffraction grating. Believes they strongly support the wave theory of light.

Refers WT to reference work to check WT's experiments [see WT's 1848-2-4]. JH says he will perform no more experiments in physical optics.