phraseology which shows the delight he took in his work, the following
beautiful experiment:--

'We took a quantity of clean lead, and melted it with a strong fire,
and then immediately pouring it out into a clean vessel of convenient
shape and matter (we used one of iron, that the great and sudden heat
might not injure it), and then carefully and nimbly taking off the
scum that floated on the top, we perceived, as we expected, the smooth
and glossy surface of the melted matter to be adorned with a very
glorious colour, which, being as transitory as delightful, did almost
immediately give place to another vivid colour, and that was as
quickly succeeded by a third, and this, as it were, chased away by a
fourth; and so these wonderfully vivid colours successively appeared
and vanished till the metal ceasing to be hot enough to hold any
longer this pleasing spectacle, the colours that chanced to adorn the
surface when the lead thus began to cool remained upon it, but were so
superficial that how little soever we scraped off the surface of the
lead, we did, in such places, scrape off all the colour.' 'These
things,' he adds, 'suggested to me some thoughts or ravings which I
have not now time to acquaint you with.'[13]

He extends his observations to essential oils and spirits of wine,
'which being shaken till they have good store of bubbles, those
bubbles will (if attentively considered) appear adorned with various
and lovely colours, which all immediately vanish upon the
retrogressing of the liquid which affords these bubbles their skins
into the rest of the oil.' He also refers to the colour of glass
films. 'I have seen one that was skilled in fashioning glasses by the
help of a lamp blowing some of them so strongly as to burst them;
whereupon it was found that the tenacity of the metal was such that