WCP174

[1] ¹

Parkstone, Dorset.

April 27^th. 1902

My dear Will

I sent you the sextant & book. It would ^be an interesting and useful experience for you to choose some high position where you could see some miles all round. Then measure a base line on some level spot, about 10 or 20 chains longs with great care. Put a permanent mark — a good stout peg driven in level with the ground — at each end. On fine days take angles from each and of base to any visible points — towers, houses, &c. and then calculate the distances. By doing a number of these you would have the materials for a map sketching in the details, & you could then compare your results with the Ordnance Map. As a test of your angles those all round the horizon added together should make 360o. Repeat them till they come right.² By means of equal angles altitudes [2] of the sun before and after noon, the mean of the two directions with a slight correction for change of declination in the interval, would give you the true south line.

For common surveying of fields &c. & to determine boundaries, the best way is to measure by triangles only, with a good chain, and plotting each line on a large scale, from 1 chain to an inch for small areas, to 3, 4, or 6 chains for large estates. The essential things are, to lay out your lines quite straight, using numerous straight rods; — to measure on steep ground with half or even a quarter of the chain [3] held horizontally, — to keep a field book in proper form, — and to measure the base lines over twice to avoid important errors. You must also make numerous permanent marks — pegs, gates &c. for cross lines or reference.³

Bingo has not been well, & I suppose did not feel inclined to do any digging alone, as he never came. I do not think the place will be touched till you come as there is too much to do.

There is not much visible about the house this week. The walls inside & back have been going up and the joists of ceilings h are being got in. My large pond has been filled & is water tight, & I have put my red water-lilies in it. The large tank in the Greenhouse has been filled also, and leaks, so bad that the inside partition wall must be pulled down & [4] rebuilt in cement as it ought to have been at first. I have let the nurseryman at Christchurch have some spare pieces of my water-lily & he is going to give me in exchange several other handsome kinds, & some good garden plants besides, of my choice, so that my pond will soon be well stocked. The orchard trees are now mostly coming into flower & leaf, and look very nice. I should think you would like to come after the roof is on the house, which will be I hope in another month, or so. About midsummer would be a good time, as you could then help us decide about modes of inside finishing. I am glad you have found some more socialists among your mates. It ^(socialism) certainly goes ahead. I enclose a long letter by an erratic but clever correspondent of mine who thinks he is the only rational socialist. Try if you can follow his money[?].

Your affectionate Pa | Alfred R. Wallace⁴ [signature]