# How much is fifty candle power in modern terms? **URL:** \ **Category:** Factual Questions\ **Created:** [May 17, 2015, 5:02pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248 "2015-05-17T17:02:54Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [May 17, 2015, 5:02pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/1 "2015-05-17T17:02:54Z")
I came across this in the _New York Times_ for April 26, 1884. > [@](#): > > A very beautiful design for a front-hall girl is now on exhibition at the company’s office, No. 409 Gold-street. The present system of lighting the front hall of a dwelling-house has the disadvantage that the light – whether it be a gas light or an electric light – must be kept burning all the evening, and that a servant must be employed to answer the bell. Thus there is a double expense – the cost of the light and the cost of the servant. The Electric Girl Lighting Company will furnish a beautiful girl of fifty or a hundred candle power, who will be on duty from dusk until midnight – or as much later as may be desired. The girl will remain seated in the hall until some one rings the front-door bell. She will then turn on her electric light, open the door, admit the visitor and light him into the reception room. One girl thus performs the duties of lighting the front hall and answering the bell, and her annual cost is much less than that of a servant and a gas light. If, however, any householder should desire to keep the electric girl constantly burning and to employ another servant to answer the bell, there can be no doubt that the electric girl, posing in a picturesque attitude, will add much to the decoration of the house. Yes, this is one of the nuttiest ideas even for the early years of electricity, when everyone was besotted by electric light. In fact, I’m arguing that the full article shows it to be a spoof, an early version of Poe’s Law. Just to make this more understandable I need to convey just how bright fifty or a hundred candle power was. From poking around I settled on saying that you can think of that as more or less equivalent to a 50 or 100 watt incandescent bulb. Am I right? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 17, 2015, 5:34pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/2 "2015-05-17T17:34:36Z")
The rough conversion is 1 candlepower = 12.57 lumens, and a 60 watt incandescent bulb would produce 900 lumens. So 100 candlepower would be equivalent to an 83.8 watt incandescent bulb. All the sources indicate it’s not that simple to calculate because of the differences in what is being measured but your approximation sounds pretty good. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [May 17, 2015, 5:58pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/3 "2015-05-17T17:58:31Z")
I’m trying to figure out what exactly that company is providing–is it just a woman holding a lamp on an extension cord? Or a flashlight? ---
**Author:** ![marking](https://avatars.discourse-cdn.com/v4/letter/m/4da419/32.png) [@marking](https://boards.straightdope.com/u/marking)\ **Post date:** [May 17, 2015, 6:11pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/4 "2015-05-17T18:11:21Z")
The company “will provide a beautiful girl of 50 or 100 candlepower who will…” In this sense, is a candlepower a unit of beauty ? (Like a milliHelen) Just wonderin’ ---
**Author:** ![Learjeff](https://avatars.discourse-cdn.com/v4/letter/l/94ad74/32.png) [@Learjeff](https://boards.straightdope.com/u/Learjeff)\ **Post date:** [May 17, 2015, 6:34pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/5 "2015-05-17T18:34:42Z")
Are lumens and candlepower really convertible without other facts? My recollection is that candlepower is a measure of the brightness (luminous intensity, corresponding to SPL if it was sound), whereas lumens measures total output corresponding to watts, if it was sound). That is, one is amplitude, the other is energy flow rate. If it radiates spherically with equal intensity in all directions, then I suppose there’s a trivial conversion to lumens. ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [May 17, 2015, 6:36pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/6 "2015-05-17T18:36:09Z")
> [@Ethilrist](#): > > I’m trying to figure out what exactly that company is providing–is it just a woman holding a lamp on an extension cord? Or a flashlight? It’s a woman with lights attached to her clothing. The year the article came out, there was a groundbreaking ballet in London, where they sewed electric lights into the costumes, then turned down the theater lights, and the whole thing was done in the dark, illuminated just by the ballerinas. ---
**Author:** ![Learjeff](https://avatars.discourse-cdn.com/v4/letter/l/94ad74/32.png) [@Learjeff](https://boards.straightdope.com/u/Learjeff)\ **Post date:** [May 17, 2015, 6:37pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/7 "2015-05-17T18:37:13Z")
> [@marking](#): > > The company “will provide a beautiful girl of 50 or 100 candlepower who will…” > > In this sense, is a candlepower a unit of beauty ? (Like a milliHelen) > Just wonderin’ 🙂 A girl beautiful enough to launch one ship! ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [May 17, 2015, 7:50pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/8 "2015-05-17T19:50:02Z")
From [here](http://www.primetimelighting.com/candlepower-lumens-footcandles), one Candle = 12.57 Lumens (into a sphere), so 50 candlepower = 628 lumens. A typical 60W lamp is around 900 Lumens, so 50 Candlepower = 41W (incandescent). ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [May 17, 2015, 10:26pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/9 "2015-05-17T22:26:44Z")
> [@Captain\_Amazing](#): > > It’s a woman with lights attached to her clothing. The year the article came out, there was a groundbreaking ballet in London, where they sewed electric lights into the costumes, then turned down the theater lights, and the whole thing was done in the dark, illuminated just by the ballerinas. The article starts with a mention of illuminated ballet girls, which I believe was the source of the whole spoof, a current event on which to hang it to make it more believable. However, the references I’ve found are to the premiere of La Fanandole, which took place in Paris in December 1893. That was covered heavily in Scientific American and electrical journals in early 1884. The only references to a similar event in London I’ve found are to an opera at the Savoy with electric lights on the chorus girls playing fairies in 1882. Do you know of another example from London in 1884? If so, I’d appreciate any information and references you could provide. ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [May 18, 2015, 12:02am UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/10 "2015-05-18T00:02:01Z")
> [@Exapno\_Mapcase](#): > > Do you know of another example from London in 1884? If so, I’d appreciate any information and references you could provide. Here’s a reference to it in the Pall Mall Budget: > **[The Pall Mall Budget](https://books.google.com/books?id=ZrY_AQAAMAAJ&pg=RA3-PA14&lpg=RA3-PA14&dq=%22electric%2Bballet%22%2Blondon&source=bl&ots=iO57JKVFcx&sig=KOB9vRp5N_EhCeAdTCS1yNYO0zc&hl=en&sa=X&ei=HitZVfLOJoamNrPNgZAI&ved=0CEMQ6AEwBg#v=onepage&q=%22electric%20ballet%22%20london&f=false)** The article refers to an electric ballet at the Empire Theater in London, directed by an M. Armand Levy, who got the exclusive rights to put on electric ballet in England. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [May 18, 2015, 12:33am UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/11 "2015-05-18T00:33:01Z")
That’s dated April 25, 1884, which presents a real problem. Today’s magazines are dated a week ahead: the date on the cover is the date they should pulled _off_ the newsstands. I don’t know if that was the practice in 1884, and even if so I don’t see how it could have gotten to the U.S. in a week. The fastest trip ever up to that time was earlier that month, with a time of 6 days, 10 hours. That’s an impossibly small window for creating such an article. The article itself talks about the appearance of lights onstage “a year ago” so even the Paris ballet is a bit late. That’s a great find, though, and I’ll definitely use it, but I don’t think that was the referent. ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [May 18, 2015, 3:22am UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/12 "2015-05-18T03:22:55Z")
I’ve also, related to that, probably referring to the same production, found this, from the Southern Medical Record of October 1884 (The Southern Medical Record was, as the name suggests, primarily a medical journal, but it also had brief stories about interesting, unusual, or funny developments in science): > **[The Southern Medical Record](https://books.google.com/books?id=JN1XAAAAMAAJ&pg=PA392&lpg=PA392&dq=%22electric%2Bballet%22%2Blondon%2Bsouthern%2Bmedical&source=bl&ots=6qTAstQwvx&sig=0FgJ8ZJNkXL_pqA-sgTf4Tkvaxo&hl=en&sa=X&ei=L1hZVf77GsuuggT_p4HoAQ&ved=0CCkQ6AEwAA#v=onepage&q=%22electric%20ballet%22%20london%20southern%20medical&f=false)** Here’s the complete article: > [@](#): > > London is to have an electric ballet. The stage will be darkened for a moment only to be instantaneously illuminated with hundreds of ballet girls in armor and every part of it pricked with stars of electric light. An ingenious Frenchman is the author of this device. When he arrived at the Charing Cross Station with his ballet dresses and machinery, he was promptly arrested as a Parisian Fenian, and had to prove his connection with the theatrical trade before he was released. And looking back, it looks like the Medical Record got that from a New York publication, “The Electrical World”, published on April 12, 1884. > **[Electrical World](https://books.google.com/books?id=icQhAQAAMAAJ&pg=PA123&lpg=PA123&dq=%22parisian%2Bfenian%22%2Blondon%2Bballet&source=bl&ots=Vpu44CUvJH&sig=PHPV4EdcP_NVGJCbTAdSIWhIqGI&hl=en&sa=X&ei=VVtZVdziGZLigwS1x4GwCQ&ved=0CDQQ6AEwAg#v=onepage&q=%22parisian%20fenian%22%20london%20ballet&f=false)** ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [May 18, 2015, 3:33am UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/13 "2015-05-18T03:33:51Z")
Sorry to add this, but I’m finding that article in various US newspapers at the beginning of April in 1884…the New Orleans Times Picayune, the Salt Lake Herald, the Raleigh News and Observer, the Wahpeton Times in what was then Dakota Territory. My guess is that the article comes from one of the news agencies…AP or Reuters, both of which existed then, and was part of their newsfeed. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [May 18, 2015, 3:46am UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/14 "2015-05-18T03:46:54Z")
Keyword searches keep coming back to that Electrical World article of April 12, which I found earlier but doesn’t give enough information. I did find the British Newspaper Archive which includes the Pall Mall Gazette, so I’ll search through that tomorrow to see if I can pin down an article from earlier in April. Thanks for the continuing help. ---
**Author:** ![Captain\_Amazing](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@Captain\_Amazing](https://boards.straightdope.com/u/Captain_Amazing)\ **Post date:** [May 18, 2015, 4:11am UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/15 "2015-05-18T04:11:28Z")
It’s a later newspaper, this one from May, but the Oamaru Mail, in New Zealand, gives more information: [http://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&d=OAM18840517.2.7](http://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&d=OAM18840517.2.7) ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [May 18, 2015, 2:16pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/16 "2015-05-18T14:16:15Z")
I registered for the British Newspaper Archive, which gives you a month at a special rate of one pound if you use the promo code SOG15. The Pall Mall Gazette original is from [March 15, 1884 p3](http://www.britishnewspaperarchive.co.uk/viewer/bl/0000098/18840315/004/0003). It doesn’t say more than the later versions. ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [May 18, 2015, 3:27pm UTC](https://boards.straightdope.com/t/how-much-is-fifty-candle-power-in-modern-terms/720248/17 "2015-05-18T15:27:43Z")
> [@Captain\_Amazing](#): > > Here’s a reference to it in the Pall Mall Budget: > > [The Pall Mall Budget: Being a Weekly Collection of Articles Printed in the ... - Google Books](https://books.google.com/books?id=ZrY_AQAAMAAJ&pg=RA3-PA14&lpg=RA3-PA14&dq=%22electric+ballet%22+london&source=bl&ots=iO57JKVFcx&sig=KOB9vRp5N_EhCeAdTCS1yNYO0zc&hl=en&sa=X&ei=HitZVfLOJoamNrPNgZAI&ved=0CEMQ6AEwBg#v=onepage&q=%22electric%20ballet%22%20london&f=false) > > The article refers to an electric ballet at the Empire Theater in London, directed by an M. Armand Levy, who got the exclusive rights to put on electric ballet in England. Thanks for the article reference; that’s actually a fascinating insight into how amazing the electric light must have been at the time. There were only three lights per dancer, apparently mounted in a jeweled reflector. Each “ballerina” was carrying a battery 7" x 2" x 4" weighing three pounds (carried behind a shield). So they weren’t so much doing ballet in terms of the classic whirling and pirouettes, which would have been mighty awkward with the bulky, heavy batteries and stiff cloth-covered wires of the period. Anyone remember those “dry-cell” batteries they used to use for big flashlights? It must have been something like that, unless they were still using lead-acid batteries – those would have been fun to be dancing around with.