cycles to hertz - when?

People stuck them on the rear mudguards and wired them to the existing single rear light (which also lit the number plate) so they had three lights to the rear. I don't know whether cars had brake lights at the time.

I can just remember my parents car - bought in 1935. As you say: one light fitting atb the back which lit the rear numberplate as wellas showing red to the rear. No reflectors or other rear lighting.

Still have the scar on the palm of my hand and I wasn't even touching the conductor. Just a shade under 1kw @27Mhz from a bank of PL519s and the spark jumped from the antenna to my hand when some idiot keyed up the rig. My fault for not locking it out I guess.

Interestingly my partner works at a place where they do RF welding, lots of warnings/safety interlocks etc. And so there should be.

Are you sure about no reflectors? Even bicycles had them in the 20s I think, as they are passive.

I don't think it did. Islamic means related to or of the religion in question, whereas

Islamist (noun) an advocate or supporter of Islamic militancy or fundamentalism. (adjective) relating to, advocating, or supporting Islamic militancy or fundamentalism.

So while "islamist" might be regarded as an extremist subset of "islamic", the word "islamic" itself is not syn Islamist (plural Islamists)

(now rare) A Muslim. [from 19th c.] A scholastic Muslim who specializes in Muslim academics. [from 1910s] A Muslim who espouses Islamic fundamentalist beliefs. [from 1980s]

#Paul

But were two rear lights actually illegal? If not, it may have been unusual but not impossible. I think I've seen some 1940s/50s cars with one central brake light but still two tail lights.

Hard to believe that one light front or rear was ever legal, since side/head and tail/brake lights serve to define the width of the vehicle to other vehicles (oncoming or approaching from behind).

But even now the Highway Code and Constructions and Use rules baffle me in terms of what they permit which I would say was wrong:

- permitted to use dipped headlights (only sidelights) in a street-lit section of road (I'd say that lighting up regulations should mandate dipped headlights, not just sidelights, irrespective of whether the road is lit or not)

- allowed to place indicators next to dipped headlights or brake lights, rather than mandating that they are spaced far enough away (eg in or under bumpers) that they can still be seen against brake/head lights.

- permitted to have just one rear fog light, rather than requiring two of them, co-sited with the tail lights (since tail and fog lights do the same job of defining the width, as seen by someone behind - just different brightness depending on whether there is fog)

I tend to make a distinction based on airfield being for military or privately chartered flights; airport being larger and for scheduled flights.

I would imagine that Angstroms fell out of use around the time that normal scientific and engineering practice was to use powers of 10 which are multiples of three: eg 1-999x 10^-9, 10^-6, 10^-3, 1, 10^3, 10^6, 10^9. And not to use powers that are in between - eg the ridiculous 0-70 x 100 rpm (as opposed to 0-7 x 1000 rpm) on older car rev counters.

Probably not mandatory to have two, but also not mandatory to have only one - so you can have either one or two.

Reversing lights ditto.

As late as that? Wow! I presume it had been common practice for a fair time before it became compulsory.

When did they finally outlaw (in the UK) the use of red rear indicators (flashing brake lights) and white front indicators (flashing side lights). My mum's 1959 Morris Minor originally had Trafficators, then these were supplemented by flashing red/white indicators, then I remember Dad having it further modified in the late 60s to have separate amber indicators front and back. Maybe the late 60s is when red/white indicators became illegal. The trafficators were not actually disabled and continued to pop out in conjunction with the flashing indicators until they finally jammed - maybe at that point they were disconnected to prevent the solenoid being permanently powered whilst ever the indicators were on, instead of switching itself off as soon as the arm had become "fully erect".

I can remember early Ford Cortinas (the pre-Aeroflow model, with the very long gear lever and the rigid metal arms that stuck out either side of the steering wheel for indicator, lights, wipers flip-switches) and they had oval sidelights which doubled as (white) front indicators; I presume right from the start the Cortina used the iconic Trivial Pursuit / CND three-segment rear light clusters.

I suppose you just killed the really naughty ones?

Bill

Or three, or more.

Bill

Ah, your thinking is anachronistic. It didn't occur to anyone that the width of the other vehicle was worth marking. they hadn't thought that far. The lights were simply to let you know the other vehicle was there. After that it was up to you.

Bill

Yes, of course. They are linked by a simple equation:

Wavelength = hc/E where h=Planck's constant c=speed of light E=photon energy

Many of the posher horse drawn carriages had lights on both sides, we had a set from a long disappeared vehicle ,candle lit with a spring to push the candle up through a hole as it burned .Frontwards clear in a vertically oriented glass about 4? x 5? and to the rear a small circular window about

They would be mounted one each side, obviously horse drawn won?t come under motor vehicle regulations but I can?t see them being illegal for powered vehicles when custom and practice already allowed for two. More likely the reason for one rear lamp on many prewar cars was that once they gave up fitting oil ,acetylene lamps and fitted electric only having one rear lamp eased the load on the early electrical systems, ICBW but I think some didn?t even have a dynamo and relied on the battery being charged between journeys.

Isn?t the idea that it extends the range of when the vehicle can be seen? Once you have seen the bright foglamp you would be slowing down till you saw the normal rear lights or stay back anyway and follow at a safe distance. width of the vehicle won?t matter before that unless you want to gamble at overtaking in fog.

GH

The state of Indiana attempted to redefine pi to be exactly 3 (in 1897).

Robert

The 'grad' being a 100th of a right angle.

Robert

What I find annoying is the weird pronunciation of Islamist - as iz-la-MIST (instead of the obvious iz-LAAM-ist).