The Lemon Fool

Is 7 a navigational instrument? Used to measure the position of astronomical objects, with some sort of eyepiece fitted to the slotted part?

malkymoo wrote:Is 7 a navigational instrument? Used to measure the position of astronomical objects, with some sort of eyepiece fitted to the slotted part?

Not navigational. I think the slot is to allow the bubble to be seen when the movable arm is in one of the higher positions.

It does have a sight: note the groove bottom left and the hole bottom right. There is a pointed pin in the hole, and the groove has a small hole where it looks like there should be a corresponding pin pointing the other way so that the points could be lined up for sighting. I do not know the purpose of this sight, however. As far as I know, the sight would not normally be used (but IANAE).

Julian F. G. W.

Is 1 a flash bulb - use once only?

Rover

Rover110 wrote:Is 1 a flash bulb - use once only?

Yes, it is a Philips "Photoflux" type PF 100 flash bulb.

You should get roughly the right exposure 100m away from the subject at f/4 and ISO 400 (1/25s X-sync).

There is currently only one manufacturer of flash bulbs in the world, Meggaflash in Ireland.

There are some examples of photographs here, http://www.meggaflash.com/index.php/flashbulb-gallery .


Julian F. G. W.

jfgw wrote:
You should get roughly the right exposure 100m away from the subject at f/4 and ISO 400 (1/25s X-sync).

Julian F. G. W.

100m. That is quite a bright flash!

RC

ReformedCharacter wrote:100m. That is quite a bright flash!

RC

He's a weapons-grade flasher!

I once had a (camera) flashlight with single-use bulbs. A toy, really, and of course once a handful of bulbs had been used it was too expensive to buy more. They were quite big and unwieldy things, but not remotely on the scale of that one!

I remember the old 'flash cubes' I used with my cheap Boot's 126 'Instamatic' (?)
Not cheap IIRC - this would be 70s/80s

ReformedCharacter wrote:

jfgw wrote:
You should get roughly the right exposure 100m away from the subject at f/4 and ISO 400 (1/25s X-sync).

Julian F. G. W.

100m. That is quite a bright flash!

RC

Even the small ones I have have a guide number of about 35m (ISO 100). These are blue ones for colour and are at least a stop slower than clear ones. I have a box of PF5B bulbs which have a guide number of 65m.

A PF5 box (clear bulbs) gives a guide number of 330' (about 108m) for 100-160 ASA (31-33 BS°)

For more light, you can tie the bulbs together with wire. The heat from one will ignite the others.

I have a box of 10 FB1B bulbs priced at £3.56. I am not sure how old they are but, if we assume 1975, they would cost about ten times that today. I will need a new 22.5V battery for my flash gun before I can experiment with them.

Julian F. G. W.

AleisterCrowley wrote:I remember the old 'flash cubes' I used with my cheap Boot's 126 'Instamatic' (?)
Not cheap IIRC - this would be 70s/80s

Those were electrically fired, just like my big bulb. There were also Magicubes which were fired by striking a pin and didn't need a battery.

There was the flip flash with ten bulbs in one package. The heat from the first bulb would melt a link and cause another link to short so as to connect the next bulb into the circuit. After five flashes, the flip flash had to be inserted the other way up to use the other five. I think there may have been one or two other types too.

Julian F. G. W.

Surely:

1. Is an old fashioned (very old fashioned) single use photo flash bulb, as used by 1950s press photographers? [Oh. Already answered!]

2. Looks like a miniature vidicon tube (thermionic video camera)?

10. Liked the suggestion it was for discharging high voltage capacitors, or CRT tubes! The alligator clip could be for a ground/chassis connection so could it be for test purposes: putting a ground loop on circuits in turn to pick up one end, or to operate a relay?

"...or CRTs!"

XFool wrote:2. Looks like a miniature vidicon tube (thermionic video camera)?

That's what it is! It is a vidicon tube out of a CCTV camera.

If I have measured it correctly, it is a 3/4" tube. The maximum diagonal of the image on a vidicon tube is about 2/3 of the tube size. For this tube, it would be 0.5". This conveniently gives an image size of 0.4" x 0.3" so the so the width of the image is just slightly more than half of the tube size.

Modern digital sensors (when expressed as an inch size) are sized the same way. If you have a "Micro Four-Thirds" camera, the image size is 17.3 mm × 13.0mm. (4/3" is about 33.9mm.) Similarly, a 1" sensor senses an image size of 12.8mm x 9.6mm.

XFool wrote:10. Liked the suggestion it was for discharging high voltage capacitors, or CRT tubes! The alligator clip could be for a ground/chassis connection so could it be for test purposes: putting a ground loop on circuits in turn to pick up one end, or to operate a relay?

XFool wrote:"...or CRTs!"

Discharging CRTs is the correct answer.

That's six items correctly identified. The purpose of the clinometer hasn't been identified yet and the other three have had no guesses at all. I might give some clues later.

Julian F. G. W.

The clinometer is interesting. For instance: How does it work?

How does the 'vernier' work to measure minutes by sliding along the square bar? Is that bar not of constant dimensions end to end and the bubble level is spring loaded, or clamped, to hold it against the bar, allowing its orientation to alter slightly from one end of the bar to the other? I can't see how else it can work.

There is a flat, vertical plate to the right side of the clinometer, suggesting in use it is placed in a rectangular corner of something. It measures no more than 45 degrees from the horizontal and measures to minutes rather than simply degrees.

It can't we used for say, gun elevation, as it measures downward slopes! I wonder if it is something to do with stability of some kind. I can't really see it's proper use but I can't help the feeling it is used to measure the exact angle at which something will start to slide or topple.

I reckon I deserve a half-point for discharging capacitors, as the CRT is acting like a big HV cap!!!!
The clinometer is clearly used to determine the angle at which buses tip over when on an inclined test platform

XFool wrote:How does the 'vernier' work to measure minutes by sliding along the square bar? Is that bar not of constant dimensions end to end and the bubble level is spring loaded, or clamped, to hold it against the bar, allowing its orientation to alter slightly from one end of the bar to the other? I can't see how else it can work.

The bar is slightly curved.

I suggest that you read through the rest of your post and question what you have written.

Julian F. G. W.

AleisterCrowley wrote:I reckon I deserve a half-point for discharging capacitors, as the CRT is acting like a big HV cap!!!!
The clinometer is clearly used to determine the angle at which buses tip over when on an inclined test platform

Half-point awarded!

The clinometer has nothing to do with buses.

If you are quick and question some of the things in XFool's post before he does, you might get a clue.

Julian F. G. W.

AleisterCrowley wrote:I reckon I deserve a half-point for discharging capacitors, as the CRT is acting like a big HV cap!!!!

Yes! Why not?

AleisterCrowley wrote:The clinometer is clearly used to determine the angle at which buses tip over when on an inclined test platform

That thought crossed my mind as well. Though I would have thought that would be built in to the test rig - something like a big dial with a hanging pointer.

XFool wrote:That thought crossed my mind as well. Though I would have thought that would be built in to the test rig - something like a big dial with a hanging pointer.

One on the bus, one on the jig:

http://i.imgur.com/IWo57xw.jpg

OK. I cheated.

https://victoriancollections.net.au/ite ... 139cbacff2

Ah! Used pointing to the left for elevation. Up is Down, depends which way you look!

XFool wrote:OK. I cheated.

https://victoriancollections.net.au/ite ... 139cbacff2

Also known as a Gunner's Quadrant. Early ones were wooden with a plumb bob.

XFool wrote:There is a flat, vertical plate to the right side of the clinometer, suggesting in use it is placed in a rectangular corner of something. It measures no more than 45 degrees from the horizontal and measures to minutes rather than simply degrees.

Up to 45 degrees standing on its base, or 45 to 90 degrees standing on its feet.

My one is marked thus:

CLINOMETER, FIELD MARK IV No 811
TAYLOR, TAYOR & HOBSON LTD [Arrow symbol] 1915

So it would have seen action in World War One. Unfortunately, I do not have the original box.

Julian F. G. W.