THE SANITAEY INFLUENCE OF FORESTS 19 



the north-west wind that the milk flow is decreased on windy days. A large 

 dairy owner north of Smith River, who weighs each day the amount of milk 

 produced by his herd, states that in spring and summer the amount of milk 

 falls off as much as 1 6 per cent during the windiest days when the cattle are 

 pastured on exposed fields. 



2. Don and Chisholm, Modern Methods of Water Purification, p. 278, 

 give a map showing the way in which salt is carried inland in the west of 

 Scotland. See also W. Barr, in Journal of Hygiene, xiv. 119 (1914), on the 

 laws regulating the blowing inland of salt spray and spindrift. 



3. Observations were made by L. A. Boodle of the Jodrell Laboratory, 

 Kew, on the foliage of seven species of trees and shrubs injured at Llanishen 

 in Wales, five miles inland from the sea, by a severe gale accompanied by salt 

 spray. Examination showed that the leaves of all the species, whether 

 injured or uninjured, contained much more sodium chloride (common salt) 

 than the foliage of the same species growing in Kew Gardens. Injured and 

 unharmed parts contained the same amount of salt. This is taken up by 

 plants from the soil, which in districts close to tlie sea and for some miles 

 inland contains much sodium chloride brought by gales. The distribution 

 of the bi'own discoloration on the leaves indicated wind-withering, due to loss 

 of water, and did not seem to be due in any way to the direct elfect of salt 

 spray. C'upressns nuicrocarpa and Eumiymus jajxmica were unliarmed, whilst 

 Thuya, yew, Lawson cypress, common laurel, and Portugal laurel were all 

 injured. See Gardeners' Ohnmicle, 26th Feb. 1916, p. 119. 



4. See British Medical Journal, 12th Jan. 1901, p. 69, 23rd May 1903, 

 1>. 1189, 4th Jan. 1905, p. 62, and 3rd Nov. 1906, p. 1165, and The Lancet, 

 7th and 14th Jan. 1905. 



5. The mountain peat ])robably did not begin to form till late in the 

 Bronze Age. In the Neolithic period the temperature seems to have been 

 4° F. higher than now, and the British Isles enjoyed a continental climate 

 with prevailing cold dry winds from the north-east. After this, some time 

 during the Bronze Ago, the climate altered, and has gradually become wetter 

 with prevailing westerly winds. Plunkett, in Kilkenny Journal of Archaeo- 

 logy, xiii. 537 (1875), states that the cairns, pillar stones, and stone circles on 

 Topped Mountain in Fermanagh, which he dates as 1600 B.C., were built on 

 the original rock surface, and since then have been covered with peat of the 

 thickness of eight feet. He concludes that in the cairn-building time the 

 climate was much warmer and less humid than now. The cairns on the 

 Dublin Mountains are also covered with peat. Tlie existence of the optimum 

 climate in the Neolithic Period and early Bronze Age has been proved in 

 other ways. 



6. See Geo. B. Rigg, in Bot. Gazette, Ixi. 158 (1916), where comparative 

 tables are given of air and soil temperatures of peat-bogs and of arable land 

 adjoining. 



7. See A. Henry, "AfTorestation of Peat- Bogs and Sand-Dunes," in Country 

 Life, 22nd April 1916, p. 497. This article contains an account of a cheap 

 method of establishing maritime pine by sowing seed on cut-over bog at 

 Abbeyleix. It was republished, without the illustrations, in a book by P. 

 Anderson Graham, Reclaiming the Waste, pp. 118-127 (1916). 



8. See Femow, U.S. Forestry Bulletin, No. 7, p. 170 (1893), and 

 Economics of Forestry, p. 77 (1902). 



9. J^conomie Forestitre, i. 199, note (1904). 



