Friday, 14 April 2017

Speed of clouds

Speed of clouds 

Suppose I lie on my back and look vertically up. I can see a cloud passing overhead, and measure the time (t, in seconds) that it takes to change its angle from the vertical by one degree. If I knew the height (h, in metres) of the cloud I could calculate the distance moved by the cloud in the horizontal plane, and thus the speed (v) of the cloud in metres per second. Tan (1º) = 0.01745; so, if the cloud were 100m above me, the 1º would represent 1.745m in t seconds. (Multiply by 2.2369 to get the answer in mph.)  But I do not know the height of the cloud. Here is a possible method for determining both height and speed. 

Object: to determine the height above ground level of the bottom of a cloud layer, and its speed across the land.
Equipment: 2 observers (A & B) at 2 different known locations some 500 - 1000 m apart, 2 mobile phones, 2 astrolabes or sextants, 2 compasses, 2 pencils and paper.
Method: Observer A identifies a cloud (C) of which the shape is sufficiently distinctive to describe uniquely (e.g. "the one shaped like a hen"). He rings B and waits till B has identified the same cloud. Each observer then determines and records the inclination above the horizontal (a) of C and its compass bearing (b).
Calculation: The data is then passed to a 15 year old with a slide rule or "scientific" calculator. He is going to assume that the two compass bearings on the cloud define two vertical planes ACD and BCD that intersect at the cloud and the point D that is the projection of the cloud on the ground. The orientation and length of the line AB between the two observers is known. The point D can be identified by drawing the lines AD and BD on the map. If the observations are repeated after 1, 2, 3, etc minutes the speed and direction of the cloud can be determined. 

The angles CAD and CBD provide two series of estimates of the height of the cloud (distance CD). (Comment: If the terrain is not flat to the horizon in all directions, observers will also need a bucket of water in order to determine a "false horizon" by which to determine the inclination angles; the true inclination will be half the angle between the cloud and its reflection in the bucket.)

Tuesday, 11 April 2017

Nostalgia and Brexit

Nostalgia and Brexit

Nostalgia: “The pain of homesickness”
     I love words and was delighted to learn, recently, that the word ’Nostalgia’ means ‘homesickness’. It is a word concocted around 1688 from the Greek ‘nostos’ = returning home, and ‘algos’ = pain (c.f. neuralgia), to describe “severe homesickness treated as a disease; occasionally with fatal outcome”.
     I had an ‘aperçu’ in the middle of the night, as follows. I watched a film in bed, and my last few wakeful minutes conceived a romanticised image of coal miners in 1970 issuing from their mine at the end of the working day; grimy, tired, cheerful and fulfilled. I woke from a dream with the realization that this type of work is a thing of the past; as dated as horse-drawn vehicles. There are in Britain many thousands of people who, in the seventies, would have felt the cheerful exhaustion of manual work but who now find themselves unskilled for the present, and gloomy about the future. From 1800 to 1950 the North of England was the powerhouse of our economy. You could almost say it was the workshop-of-the-world, as they build railways for Argentine, and wove cotton saris for India.
     That glory has gone. They are left with their allotments, leeks and whippets, watching the Eastern Europeans come over to pick our carrots and mend our ball-valves. We have witnessed in a shockingly short time the redundancy of a whole social class. Could that be the real cause of the startling outcome of the Brexit referendum, at least in the north of England?  

The loss of status.
     There were two quite different reasons for voting “Leave”; but both can be described as nostalgia for loss of status.
     I doubt the ‘manual working classes’ ever thought themselves to be ‘as good as’ the landowners, or factory owners. But they could justifiably think of themselves as ‘utterly essential’ to society; and even (with justification) as ‘carrying’ the whole of society on their shoulders. Who, after all, sowed, reaped, and milled the corn, who built the houses, mined the coal? Not the vicar, nor the squire nor the school teacher. Nobody needed to feel equal, because everybody knew they were all family. Today we import much of our food, and 65% of our cars (Of the 2.4 million cars sold in UK in 2015, 35% were made here). Unemployment, at 5%, is not that different from the seventies, and is much less than in the eighties. So there are jobs; but it is not men’s work.  A degree of nostalgia for the lost status of ‘the manual worker’ is very understandable.  
     However, I meet many who admit to voting “Leave”, but who never were employed in manual work, and whose jobs are not remotely under threat from abroad. So they do not fall in that category, and are not nostalgic for a vanished personal status.  Nevertheless, I find that they also are yearning for a bygone era. Someone talked of ‘cricket on the green’, someone else wanted to revive trade with the ‘Commonwealth’. I sense, in this second category of leavers, a nostalgia for the time when this country was know (officially and throughout the world) as Great Britain. 
    
Is this the real Brexit mindset — a desire to restore the fifties, and sixties?  
     Those who voted to leave unified Europe may have made some canny calculations about wages, or realized that we are already severely overcrowded on this little island. But I doubt it. There may be incisive reasons for exit. But I do not hear them. Most ‘Leavers’, though now a little subdued, as they begin to realize the giant task ahead, still re-affirm their commitment to leaving. For them, there never was a reason for leaving, just an emotion. 

The Future
     Whatever the terms of Brexit and whatever the rôle of Britain in the next 20 years, it will NOT be as it was in the fifties, sixties and seventies.