Daguerre and his collaborator Joseph Nicéphore Niépce (who died in 1833) had been working for a decade on a more efficient photographic procedure. On behalf of the Académie des sciences, the politician and scientist François Arago had announced the perfected daguerreotype method in early January 1839. Excited write-ups of Daguerre's achievements soon began appearing across Europe as well as in the US press. The first of the latter was published in the Boston Daily Advertiser of 23 February 1839. Morse's article was printed in the New-York Observer of 20th April in the same year. It was originally written as a letter to his brothers Sidney and Richard Morse, who were the paper's editors. In the first part of his report, which I cite here, Samuel Morse describes his visit to Daguerre's "Diorama" building at the corner of rue Sanson and rue des Marais on 7 March, where he was shown examples of Daguerre's work.
Morse was especially taken with Daguerre's famous image, Boulevard du Temple, a view of the northern end of the street whose remains, post-Haussmann, now lie underneath roughly the middle of the place de la République:
The exquisite minuteness of the delineation cannot be conceived. No painting or engraving ever approached it. For example: In a view up the street, a distant sign would be perceived, and the eye could just discern that there were lines of letters upon it, but so minute as not to be read with the naked eye. By the assistance of a powerful lens, which magnified 50 times, applied to the delineation, every letter was clearly and distinctly legible, and also were the minutest breaks and lines in the walls of the buildings, and the pavements of the street. The effect of the lens upon the picture was in a great degree like that of the telescope in nature.
Objects moving are not impressed. The Boulevard, so constantly filled with a moving throng of pedestrians and carriages, was perfectly solitary, except an individual who was having his boots brushed. His feet were compelled, of course, to be stationary for some time, one being on the box of the boot-black, and the other on the ground. Consequently, his boots and legs are well defined, but he is without body or head because these were in motion.