Author Topic: 750 watt Edison bulb (Read 11207 times)

Jessica Hatcher · « **on:** March 07, 2004, 07:08:00 pm »

I am trying to research an old GE National Mazda lamp which was inherited. Forgive me as I describe this as I am new to the descriptive language. The measurements are are approximate as the bulb is in a display case thus difficult to accurately measure.
However, the bulb itself measures around 9-10 in height, with a with what appears to be a white porcelain base. Within the larger outer bulb is another tubular shaped piece of glass which measures roughly 4-5 inches.
At the top of this "tube" is a disc shaped piece of hand blown glass on which is written a5, 750, 74x (or maybe 79x). In this glass disc the filaments are melded.
The base of the bulb has the patent markings, Fortunately, I have been able to find their meanings. As well, I know it is a 750 watt bulb and i believe the a5 indicates voltage(?). The 74(or79)x has me puzzled. The base markings I have identified. I know a picture would be the best way to go about this but I am in the process of a move and it may be a while before I can accomplish this.
The story behind the bulb goes ... My husbands great uncle by marriage, inherited it from his father who was friends with Edison. One day over lunch, my husbands great uncle's father told Edison he was having trouble reading and needed a brighter lamp. A couple of days later, Mr. Edison brought him the lamp. However, after only one burning, he packed it away. Certainly, it was bright enough, but he said it gave off so much heat he couldn't stand to be in the same room with it! Although all the old documents would appear to back up this story, you never can tell...
If anyone could help with any information on this, I would be most appreciative. Thank you. Jessica

Yoshi · « **Reply #1 on:** March 07, 2004, 11:55:00 pm »

I'd need a picture to say anything about your bulb.

Mónico González · « **Reply #2 on:** March 08, 2004, 08:27:00 pm »

A cool story to want to know more about that particular lamp!
A picture of it would be very appreciated!

Best regards,
M. Gonz?lez.
http://mis-bombillas.webcindario.com

Tim · « **Reply #3 on:** March 22, 2004, 10:07:00 pm »

Picture posted on Jessica's behalf:

------------------
Tim
Kilokat's Antique Light Bulb Site
Mountain Dew Collectibles, Volume I

Yoshi · « **Reply #4 on:** March 25, 2004, 02:57:00 am »

WOW... well, in my opinion, that is a very rare and significant lightbulb. And it certainly looks like a 750w bulb too. Over the years I've seen very few of those bulbs pop up on eBay (about 2 I think), and they all sold VERY well. It is called a Mazda C lamp. What makes this bulb so rare, I believe, is that it was made ONLY in the year 1914 (according to the book, "The history of the incandescent lamp" by J.W. Howell and Henry Schroeder, page 152). By 1915 the Mazda C lamp looked completely different.

A very coveted lightbulb in my opinion.

Please note that the porcelain 'base' that the bulb sits in is a socket and can be unscrewed from the bulb easily. (it is called a 'mogul' socket).

Jessica Hatcher · « **Reply #5 on:** March 25, 2004, 10:38:00 am »

Thank you so much for your information. I have e-mailed the Edisonian for more information and perhaps an appraisal. For years, we have had this lamp tucked away because we have small children and did not want to take the risk of something tragic happening to it. Until now, we have never even shown it to anyone. However, it seems a shame that no one, particularly collectors, can enjoy it. Ignorant on the subject, we have always been impressed merely by it's size. Nevertheless, I contacted the Smithsonian and e-mailed pictures on Monday. We are hoping they will take the lamp on loan, safely placing it in their collection. I am interested in insuring it. When I spoke with the gentleman at the Smithsonian, he explained he could not appraise the bulb because he works for a government agency and had always referred people to Dr. Hicks in Baltimore until his passing. Should the Edisonain be unable to offer an appraisal, do you have any suggestions?
Again, I thank you for your time and information.
Best regards,
Jessica Hatcher

[This message has been edited by Jessica Hatcher (edited March 25, 2004).]

Mónico González · « **Reply #6 on:** March 27, 2004, 07:04:00 pm »

Hi Jessica!
Before nothing, I must apologize for have been delayed on reply you.
I received your email some days ago, but I've been too busy and had no spare time for reply.
The lamp in fact, looks like a huge gasfilled bulb fitted with a single-coiled zig-zag shaped tungsten filament.
As Yoshi says, it seems to be a very little previous to the legendary "Mazda C".
In fact, the major differences between these two bulbs are about the filament structure and envelope shape.
This particular bulb, as can be seen, has a zig-zag filament structure, as can be seen in most mid-to-high power lamps including projection bulbs.
The "Mazda C" has a flat "C" shape filament, the same that can be found in many modern low power gasfilled household bulbs.
The second difference are relative to the bulb shapes.
The "Mazda C" was one of the first bulb that was fitted with "GT" (spherical with a cylindrical neck) envelope, the predecessor of actual "A" shape.
Your bulb are fitted with an "S" globe, also known as "pear shape".
A detail to point out is that your bulb are exausted by means of the upper tip instead through the stem as modern lamps.
Hmmm... 750 watts; really a powerful lamp to stand near it when lit. Perhaps in December or January... light and heat.
About the white sleeve at the cap, it seems like a Mogul ceramic socket to the lamp can be screwed on and displayed without any damaging risk.
As Yoshi says, the lamp can be unscrewed out of it.
If you want to see a similar filament structure, please go to the following link:
http://mis-bombillas.webcindario.com/Altrilux_220_500.htm

Best regards,
M. Gonz?lez.
http://mis-bombillas.webcindario.com

[This message has been edited by M?nico Gonz?lez (edited March 28, 2004).]