From Horace Darwin to G. H. Darwin 24 February 1878

Dear George

It is £1—1^d a day   I think I should have struck for that a week, I have been rather slack for the last few days so only charge $\frac{1}{2}$ time. I have to sit up till 2 tonight and take the pressures of the water with a gauge at every hour from 10 till 2, I go out with a key a lantern & a bar to turn the key & the gauge, lift up a F.P. cover in the pavement screw on the gauge & take the reading; in the day I have an admiring crowd round me each time but I suppose it will be quiet to night. I d’ont think that when it is done it will be much good the gauges are not nearly accurate enough; for instance at one place the main from the reservoir splits into two & I have proved that more water flows away from the junction by the two pipes than arrives by the one, this showing —ive leak! I have still got my rooms at Cam. I had taken them to Easter, but I do’nt expect I shall be back by then. The blinds were not up but I don’t know what state they are in. Blore has one of his invention put up which is not much good John says.

Old Shafto does seem a oner. I think it is positively indecent reading the morning service to one self. The weather has been perfect here, I sat on the beach one morning in the sun for a long time watching the sea, there was no wind & fine long rollers. I tried an experiment at Goldstone yesterday (Sunday) with Baker. A B a 15″ pipe [DIAG HERE] standing full of water up to C about $\frac{1}{2}$ mile long, no water running through it

D a water tight valve which keeps it full, when the engines are going this pipe takes water up to Reservoir at B, but they were not going when I was there.

E a 3″ pipe with cock in it. I put an indicator on at F & partly opened (slowly) the cock in 3″ pipe, & the pressure went up (about 1lbs) where as it ought to have gone down, & I cant in the least understand it; after a minute the cock was fully opend suddenly & that made the pressure go down wh. was right, & when the cock was shut the pressure went up wh was also right; & then went oscilating up and down for some time, wh. I don’t quite understand   I must try that again. & try & make it out.

I have two theories

Yours ever | H Darwin