Asserts that a process for obtaining 'Turnbull's blue' recently published in PN was discovered and published in 1842 by JH. Adds a second case in which JH anticipated another author's result.
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Asserts that a process for obtaining 'Turnbull's blue' recently published in PN was discovered and published in 1842 by JH. Adds a second case in which JH anticipated another author's result.
Notes introduction of 'Worthytype' process into commercial photography. Calls attention to process discovered by JH in 1832 for purifying uranium.
Points out that [Joel?] Spiller's article, 'Hyposulphite of Ammonia for fixing,' is 'copied verbatim' from a work of JH's.
Discusses the possibility of stereoscopic photography of action scenes. Also speculates about color photography.
[Writing under the pseudonym 'Redde Suum Cuique'], JH notes that a recently published process for recovering silver from old plate was in fact anticipated by James Keir in a 1790 R.S.P.T. paper. Attacks a recent misuse of the word 'actinometer.'
Describes a method created by JH [see JH's 'Lettre ... sur ... un nouveau procédé pour effectuer la purification complète de l'oxide d'urane,' Annales de chimie, 49 (1832), 306-11] for obtaining pure uranium.
Discusses recent progress in color photography. Stresses that what is most needed is a way of making negatives from which colored positives can be produced. Recounts JH's recent experiments relating to the action of light on solutions of platinum.
Reveals the solution to a cipher given in JH's 1865-12-28 letter to PN.
Maintains that JH did not invent the thaumsacope [thaumatrope], which some have ascribed to him. JH does note that he proposed moving pictures in an 1860 publication, five years before Alonzo G. Grant sought patent protection for this idea.
Discusses the action of hyposulphite of ammonia on muriate of silver. Gives directions for preparing hyposulfite of silver.
Quotes from an 1840 publication by JH to show JH's priority over a recent request for a patent for 'Magic pictures.' Recounts some recent photographic experiments by JH on the action of light on platinum.