The following extracts are from letters written to his wife while on his visit to Lord Rosse at Parsonstown in Ireland.  On the way he stopped at Bangor and looked at the Tubular Bridge Works, which are thus referred to:  “Stopped at Bangor, settled pro tem. at the Castle, and then walked past the Suspension Bridge towards the Tube Works, which are about 1-1/2 mile south-west of the Suspension Bridge.  The way was by a path through fields near the water side:  and from one or two points in this, the appearance of the Suspension Bridge was most majestic.  The Tube Bridge consists of four spans, two over water and two over sloping land.  The parts for the double tube over the water spans (four lengths of tube) are building on a platform as at Conway, to be floated by barges as there:  the parts over the sloping banks are to be built in their place, on an immense scaffolding.  I suspect that, in regard to these parts, Stephenson is sacrificing a great deal of money to uniformity of plan:  and that it would have been much cheaper to build out stone arches to the piers touching the water....  The Tube Works are evidently the grand promenade of the idlers about Bangor:  I saw many scores of ladies and gentlemen walking that way with their baskets of provision, evidently going to gipsy in the fields close by.”

THE CASTLE, PARSONSTOWN,
1848, Aug. 29.

After tea it was voted that the night was likely to be fine, so we all turned out.  The night was uncertain:  sometimes entirely clouded, sometimes partially, but objects were pretty well seen when the sky was clear:  the latter part was much steadier.  From the interruption by clouds, the slowness of finding with and managing a large instrument (especially as their finding apparatus is not perfectly arranged) and the desire of looking well at an object when we had got it, we did not look at many objects.  The principal were, Saturn and the Annular Nebula of Lyra with the 3-feet; Saturn, a remarkable cluster of stars, and a remarkable planetary nebula, with the 6-feet.  With the large telescope, the evidence of the quantity of light is prodigious.  And the light of an object is seen in the field without any colour or any spreading of stray light:  and it is easy to see that the vision with a reflecting telescope may be much more perfect than with a refractor.  With these large apertures, the rings round the stars are insensible.  The planetary nebula looked a mass of living and intensely brilliant light:  this is an object which I do not suppose can be seen at all in our ordinary telescopes.  The definition of the stars near the zenith is extremely good:  with a high power (as 800) they are points or very nearly so—­indeed I believe quite so—­so that it is clear that the whole light from the great 6-feet mirror is collected into a space not bigger than the point of a needle.  But in other positions of the telescope the definition is not good:  and we must look to-day to see what is the cause of this