The arrival of Frances Harriet’s fifth child, Thomas’ eighth, did not entirely preclude his continuing geological exploits. He had been invited to display various parts of his collection in Shrewsbury, for which he was awarded the medal above.
Monday The 16th [June]. I unpacked my fossils, minerals, glass etc which I lent to the Condover Industrial Exhibition, which has been open for a fortnight in the Armoury, Shrewsbury. I found them all safe, and undamaged; and I am glad to have them back safely. Mr. Wanstall wrote to say they gave pleasure and instruction to thousands.
Mr. Wanstall was the secretary of the Severn Valley Field Club, for whom Thomas had previously led expeditions, and a two day event had been arranged for the group, which began with a visit to Palé and a view of Thomas’ collections.
Tuesday the 24thI went to the station to see the Severn Valley folks pass in the train. I asked Mr Wanstall to come here about 3 o’clock. As already arranged in the programme, the members arrived here a little before 3 o’clock. There were about 20 of them. I met them here at the gate as they stopped; they came on the top of the hotel four-in-hand coach.
Mr Wanstall came into my house to give me a medal and certificate, which were awarded to me at the Condover Industrial Exhibition, which was held in the Armoury, Shrewsbury on Whit week, and the following week.
I conducted the party around the Hall first, and then along the Long or Queen’s walk, showed them the cromlech and the tree planted by the Queen. After that they inspected my collections of shells, birds eggs, plants, dried and fresh, and astonished at my collection of fossils.
Having attended a dinner with the club that evening, the next day’s excursion was to see the recently completed (1889) Lake Vyrnwy Reservoir, which Thomas had visited several times in construction with groups including the Chester Society for Natural Science
Wednesday the 25th I went by the first train to Bala, had breakfast with my friends, and started with them for the Vyrnwy Lake at Llanwddyn. Unfortunately there was a drizzling rain most of the way there. We went in 5 foot waggonettes, or brakes by the Hirnant Valley and over the watershed into the Montgomery side of the hills. The first sight of the lake was very pleasing, and would have been much more so if it had been fine. We went along the south side of the lake until we got to the great masonry dam. Here we had 2 to 3 hours to lunch and to see the works, etc. The following are some of the particulars of the gigantic works.
The general dimensions of the modern Lake Vyrnwy when full to the level of 825 feet above the sea, at which height it will begin to overflow, will be as follows– Length 4 ¾ quarter miles. Width 1 ¼ to 5/8 of a mile. Greatest depth 84 feet. The distance from the lake to the Town Hall Liverpool is 77 miles. This is the longest aqueduct yet constructed. From the lowest available level of the lake to the top water level of the Prescot reservoirs, the difference of altitude is 548 feet, and the length of the aqueduct to the reservoirs is 68 miles, there is an average fall of nearly 8 ½ feet per mile.
The Hirnant Tunnel – from the Vyrnwy Culvert (this is between the straining tower and the tunnel) the water flows for a distance of 2 ¼ miles through the Hirnant tunnel. The gradient of this work is 2 feet per mile, and the size such that is straight cylinder 7 feet in diameter may be passed through it. A stream of 40, 000,000 gallons per day will fill the tunnel to the depth of about 5 feet. The tunnel was driven from both ends with dynamite and air drills, the men working in three shifts, night and day.
Thomas wrote out several pages of detailed facts about the Reservoir, which he had visited at several times during the course of its construction.
After the visit the day continued with a further exploration of the area, and some botanising.
After leaving the great dam, we went over this hill to the outlet of the tunnel, near the old church of Hirnant. We crossed the line of pipes three times on our way to Pen-y-Bont-Fawr, and at Llangynog we stayed a short time to have tea. As it cleared up a little some of the party walked as far as the parsley-fern and carried off nice plants; but as it is in such abundance, there was no fear of destroying it. I found two species of Cystopteris and one or two other species of ferns. I also got the Saxifraga stellaris and Campanula hederacea for them. I got down and walked home before getting to Calethor as it came on heavy rain again. It rained heavy all the evening and continued into the night. The members much enjoyed their visit, considering the day we had.