Letter to the authors of the Journal de Paris: Daylight Savings Time | 1784-04-26 | Journal de Paris

Benjamin Franklin, Letter to the Editor, Journal de Paris, April 26, 1784. Read by M. L. Cohen, Cleveland, Ohio, March 2007. Messieurs, you often entertain us with accounts of new discoveries. Permit me to communicate to the public, through your paper, one that has lately been made by myself, and which I conceive may be of great utility. I was the other evening in a grand company, where the new lamp of Messrs. Kincaid and Lang was introduced, and much admired for its splendor, but a general inquiry was made whether the oil it consumed was not in proportion to the light it afforded, in which case there would be no saving in the use of it. no one present can satisfy us in that point which all agreed ought to be known it being a very desirable thing to lessen if possible the expense of lighting our apartments when every other article of family expense was so much augmented i was pleased to see this general concern for the economy for i loved the economy exceedingly i went home and to bed three or four hours after midnight with my head full of the subject an accidental sudden noise waked me about six in the morning when i was surprised to find my room filled with light and i imagined at first that a number of those lamps had been brought into it but rubbing my eyes i perceived the light came in at the windows i got up and looked out to see what might be the occasion of it when i saw the sun just rising above the horizon from whence he poured his rays plentifully into my chamber my domestic having negligently omitted the preceding evening to close the shutters i looked at my watch which goes very well and found that it was but six o'clock and still thinking it something extraordinary that the sun should rise so early i looked into the almanac where i found it to be the hour given for his rising on that day i looked forward too and found he was to rise still earlier every day till towards the end of june and that at no time in the year he retarded his rising so long as till eight o'clock your readers who with me have never seen any signs of sunshine before noon and seldom regard the astronomical part of the almanac will be as much astonished as i was when they hear of his rising so early and especially when i assure them that he gives light as soon as he rises i am convinced of this i am certain of my fact one cannot be more certain of any fact i saw it with my own eyes and having repeated this observation the three following mornings i found always precisely the same result yet it so happens that when i speak of this discovery to others i can easily perceive by their countenances though they forbear expressing it in words that they do not quite believe me one indeed who is a learned natural philosopher has assured me that i must certainly be mistaken as to the circumstance of light coming into my room for it being well known as he says that there could be no light abroad at that hour it follows that none could enter from without and that of consequence my windows being accidentally left open instead of letting in the light had only served to let out the darkness and he used many ingenious arguments to show me how i might by that means have been deceived i own that he puzzled me a little but he did not satisfy me and the subsequent observations i made as above mentioned confirmed me in my first opinion this event has given rise in my mind to several serious and important reflections i considered that if i had not been awakened so early in the morning i should have slept six hours longer by the light of the sun and in exchange have lived six hours the following night by candle-light and the latter being a much more expensive light than the former my love of economy induced me to muster up what little arithmetic i was master of and to make some calculations which i shall give you after observing that utility is in my opinion the test of value in matters of invention and that a discovery which can be applied to no use or is not good for something is good for nothing i took for the basis of my calculation the supposition that there are one hundred thousand families in paris and that these families consume in the night half a pound of bougies or candles per hour i think this is a moderate allowance taking one family with another for though i believe some consume less i know that many consume a great deal more then estimating seven hours per day as the medium quantity between the time of the sun's rising in hours he rising during the six following months from six to eight hours before noon and there being seven hours of course per night in which we burn candles the account will stand thus In the six months between the 20th of March and the 20th of September, there are nights, 183, hours of each night in which we burn candles, 7. Multiplication gives for the total number of hours, 1,281. These 1,281 hours, multiplied by 100,000, the number of inhabitants, gives 128,100,000. one hundred twenty eight millions and one hundred thousand hours spent at paris by candlelight which at half a pound of wax and tallow per hour gives the weight of sixty four million fifty thousand sixty four millions and fifty thousand of pounds which estimating the whole at the median price of thirty sols the pound makes the sum of ninety six millions and seventy five thousand livres tournois colon ninety six million seventy five thousand an immense sum that the city of paris might save each year by the economy of using sunshine instead of candles if it should be said that people are apt to be obstinately attached to old customs and that it will be difficult to induce them to rise before noon consequently my discovery can be of little use i answer nil desperando i believe all who have common sense as soon as they have learnt from this paper that it is daylight when the sun rises will contrive to rise with him and to compel the rest i would propose the following regulations first let a tax be laid of a louis per window on every window that is provided with shutters to keep out the light of the sun Second, let the same salutary operation of police be made use of to prevent our burning candles that inclined us last winter to be more economical in burning wood. That is, let guards be placed in the shops at the Wax and Tallow Chandlers, and no family be permitted to be supplied with more than one pound of candles per week. Third, let guards also be posted to stop all the coaches, etc., that would pass the streets after sunset, except those of physicians, surgeons, and midwives. fourth every morning as soon as the sun rises let all the bells in every church be set ringing and if that is not sufficient let a cannon be fired in every street to wake the sluggards effectually and to make them open their eyes to see their true interest all the difficulty will be in the first two or three days after which the reformation will be as natural and as easy as the present irregularity pour ce n'est que le premier pas qu'accompli oblige a man to rise at four in the morning and it is more than probable he will go willingly to bed at eight in the evening and having had eight hours of sleep he will rise more willingly at four in the morning following but this sum of ninety six millions and seventy five thousand livres is not the whole of what may be saved by my economical project you may observe that i have calculated upon only one half of the year and much may be saved in the other though the days are shorter besides the immense stock of wax and tallow left unconsumed during the summer will probably make candles much cheaper for the ensuing winter and continue them cheaper as long as the proposed reformation shall be supported for the great benefit of this discovery thus freely communicated and bestowed by me on the public i demand neither place pension exclusive privilege nor any reward whatever i expect only to have the honor of it and yet i know there are little envious minds who will as usual deny me this and say that my invention was known to the ancients and perhaps they may bring passages out of the old books and proof of it i will not dispute with these people that the ancients knew not the sun would rise at certain hours they possibly had as we have almanacs have predicted it but it does not follow thence that they knew he gave light as soon as he rose this is what i claim is my discovery if the ancients knew it it might have been long since forgotten for it certainly was unknown to the moderns at least to the parisians which to prove i need but one plain simple argument they are as well instructed judicious and prudent of people as exist anywhere in the world all professing like myself to be lovers of economy and, from the many heavy taxes required from them by the necessities of the state, have surely an abundant reason to be economical. I say it is impossible that so sensible a people, under such circumstances, should have lived so long by the smoky, unwholesome, and enormously expensive light of candles, if they had really known that they might have had as much pure light of the sun for nothing. I am, etc., a subscriber. Signed, Benjamin Franklin. End of article.