[D8805AJG], Letter from Amherst College, David Peck Todd to Thomas Alva Edison, November 24th, 1888


View document with UniversalViewer   → View document on Archive.org  → Re-use this digital object via a IIIF manifest


[D8805AJG], Letter from Amherst College, David Peck Todd to Thomas Alva Edison, November 24th, 1888

Editor's Notes

"The slender resultss obtained by astronomers from solar eclipes during the past ten years is sufficient reason for seeking additional faciliities for observing them. The two best eclipses of the century (1883 and 1886) were largely lost because the totality-path lay mostly on the ocean. The question of utilizing sea-spaces in eclipse-observation does not appear to be entirely hopeless, if we consider the marked success of [unclear] Piazza Smythe a third of a century ago, on the yacht Titania, when, by using the well-known principles of the study suspension of his telescope for a considerable length of time. The rolls of the visue were 10" each + at the rate of 25 per minute, + the pitches of the 27 per minute, + 3" each. The mechanism is apparently provisional, + perhaps made,-the fly-wheel was only one foot in diameter; + through weighing but eleven pounds, he had much difficulty in maintaining with gear wheels and cranks + velocity of nearly 100 hours per second. Press judiciously, "he says" in the [unclear] rings-and the table was adjusted 'non accurately than by any tangent-screw.' But before he had got far with his experiments, a weakness on the duplex developed + the apparatus went to [unclear]. With this, the whole thing appears to have not oblivion, but the account is a most interesting one, and is given at pp. 12-19 of Professor Smythe's book (also now quite-forgotten) entitled 'Teneriffe: an Astronomer's Experiment." [London Lovell Reeve, 1856] ### It appears to me a matter of much astronomical importantce to repeat this trial, on a larger scale, and with the vast advantage of electric motors to maintain the speed of the revolver. The next total eclipse (1st Jan. 1889) would afford an excellent opportunity for the fact, as the best part of its track is otherwise lost on the Pacific, just off the California coast; which on land, clouds seem perhaps more likely than clear skies. ### I have all the optical + photographic apparatus necessary for corona-work (the same as I used in Japan last year); while if the mechanical + electrical parts of the apparatus could be supplied by yourself, I feel confidant that through my friend Captain Koyo, President of the Lic Trustees [?], arrangements could be concluded for the nautical part of the programme. ### I shall be glad to hear whether you would be interested in such a venture; + for my own part, I should be able to give up my time to it quite exclusively for the next two months. ### Of course, I need not say that the success of the experiment might go a long way toward creating a demand for similar apparatus on ship-board generally, for use in the ordinary solar and lunar observations; this contributing to a greater precision in longitude + latitutudes derterminations at sea." Yours, very respectfully, David P. Todd [Marginalia: "I will make the apparatus free if you furnish marking drawing and the expense is not found too great." E]




Folder/Volume ID


Microfilm ID


Document ID



Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
Download CSV | JSON