RHS what-is-it?? appeal

Appeal to identify scientific curiosities of the past

A few bits 'n bobs for our eggsperts to peruse

**LINK**

Edited By Ady1 on 29/12/2021 10:18:07

…NO … This professional instrument includes a clamp; and helpfully indicates how to apply that.

There is clearly much more to the instrument than being some sort of clamp !

… Let’s have some photos of the other details.

MichaelG.

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Edit: __ I suspect it may be a Galvanometer

Edited By Michael Gilligan on 29/12/2021 10:51:06

The article doesn't have a link to the relevant site, tsk tsk tsk, the BBC eh, can't get the staff

edit: I've had a squirrel and couldn't find anywhere either

"RHS wisley scientific"

Edited By Ady1 on 29/12/2021 11:00:50

Yes I would say a Ballistic Galvanometer as well and the clamp is to lock the movement.

Looks like a mirror galvanometer to me, clamp hold mirror when not in use.

I looked up Torsion Galvanometer and found this image: note similarity with the Siemens & Halske instrument on the right.

I think one of the other BBC photos is a vacuum pump. Another is definitely an electric heating element, perhaps used to melt wax for making microscopical sections with a microtome.

Dave (who is supposed to be on his way to another family do, bah humbug,)

I think that it indicates that there are far too many media studies trained people in the BBC.

Yes it is a mirror galvanometer and yes, Cambridge Scientific Instruments made them for calibration labs around the civilised world

Edited By Mark Rand on 29/12/2021 12:02:24

Almost certainly a ballistic, or mirror, galvanometer.
I couldn't find one by Cambridge, but here's a very similar model by Pye
https://www.etsy.com/uk/listing/1020691066/vintage-192030s-mirror-galvanometer

There's several videos on youtube explaining how they work

Bill

YEP ! mirror galvanometer, PYE and CIS may have been one and the same ? Noel.

Re the brass item with the rack operated cylinders.
I'm going with a vacuum pump, but with the glass dome missing.
Here's one example
http://www.antique-clocks.com/php/details1Eng.php?ItemNummer=2760

Bill

I don't think Pye & CIS were directly related, other than an employee left the original company in 1898 and went on to form W.G.Pye . (Might have been 1896, there seems to be a date conflict on WIKI)
If I'm reading This WIKI correctly, it was made between 1895 and 1920, going by the name on the galvanometer.
https://en.wikipedia.org/wiki/Cambridge_Scientific_Instrument_Company

p.s. I've dropped RHS an e-mail query as to whether they have any further interesting exhibit photos on-line anywhere, along with a solution to a couple on the BBC site; I'm sure I won't be alone in that.

Bill.

I'm sure there are dozens of those galvanometers around schools and universities. Not impressed by the number of photos like only one angle on the first and no inside view of the chest.
I think the first item is a kill jar for bugs. A bell jar goes over the flat area, the dual action pump tries to suffocate them and the funnel can be used to introduce eg chloroform.

My sister lives near RHS and is a member so will be able to line up a visit when the new display opens.

Edited By Bazyle on 29/12/2021 15:22:45

Suspended mirror galvanometer would make sense.

It's probably on Tik Tok

Hi there, all,

Here's a minor item from the first photo:

I believe that the gizmo with the black drum is called a 'Kymograph'. It's used by botanists or botany students to measure the growth of plants. That would fit in with the RHS connection. I'm no botanist but, to the best of my recollection, you wrap a sheet of smoked paper around the drum and position the gizmo next to the plant under test. There's a clockwork motor inside the drum that rotates it at a known rate. A stylus attached to the plant bears on the drum and leaves a trace on the soot coating from which the rate of growth of the plant can be deduced. (In high CO2 levels, they grow higher and faster.)

The smaller clear object in the bottom right-hand corner of my photo is a spirit lamp. It wouldn't have been used (on its own, at least) to smoke the kymograph chart since a spirit lamp gives a smoke-free flame. In my early days of at-home chemistry experiment (in my bedroom) I used one in lieu of a Bunsen burner.

My grammar school chemistry master gave me an out-of-date catalogue from a scientific supplies firm, Townson & Mercer Ltd. of Croydon. It was even bigger than the last hard-bound Buck & Hickman catalogue, not quite a fork-lift job but pretty weighty. Browsing through it raised lots of questions like 'Please sir, what is a Kjeldahl's apparatus used for?'. An extra-curricular educational supplement!

On the subject of mirror galvanometers, with ribbon suspensions, my Senior Engineer in my first job preferred H. Tinsleys of Werndee Hall in South London. (I can't remember their full address.) I once had a guided tour of the Tinsley factory. They did some quite clever stuff with 'galvos' with multiple coils and connecting ligaments to measure power et. al..

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 29/12/2021 17:12:08

It may or not be in this edition of the company's catalogue.