176 



KNOWLEDGE & SCIENTIFIC NEWS. 



■"Al'gust, 1904. 



types of these moors can be distinguished acccrdingf to 

 the characteristic plants which grow on them; of these 

 the cotton-grass moors are by far the most extensive 

 with a vegetation in which one of the two species of 

 cotton-grass {Eriophorunt vaginaium and E. angusti- 

 folium) are the prominent forms. The other two types 

 of moors occur round the edges of the first, one type 

 being characterised by the abundance of heather 

 {Calluna Erica), the other by the essentially grassy 

 character of its vegetation. The cotton-grass moors 

 are richest in peat, which here extends to a depth of 

 10, or even 20-30 feet, whilst the other two types of 

 moor are much poorer in peat, which is usually not as 

 much as five feet in thickness and often ven.- incon- 

 siderable. When we come to inquire into the origin of 

 these peat-moors, all the evidence seems to point to 

 their being due to the destruction of an original forest. 

 Numbers of place-names occur on the Pennine slopes 



Cotton-grass .Moor in June. Cotton Grass in Fruit. 



which indicate a forest, although the onlv trace of it, to 

 be found now, lies in the buried timber, which has been 

 found enclosed in the peat. Probably the Roman in- 

 vasion was the cause of the destruction of a great deal 

 of this primitive woodland, and the fallen logs probably 

 serv-ed to dam up a number of the streams, which arose 

 on the hills, and to otherwise interfere with the drain- 

 age. The resulting swamps would readily become 

 populated by bog-forming mosses {Sphagnum, Hypnmri), 

 which are always present in the upland woods, whilst 

 the previously existing vegetation would soon be 

 smothered. From such marshy centres the bogs would 

 spread out in all directions and probably even come to 

 occupy ground which was even primarily devoid of 

 forest, .'\fter some time the remains of the mosses will 

 have formed a sufficiently consistent layer for the estab- 

 lishment of tvoical mar.sh-plants, such as the cotton- 

 grasses mentioned above, and so the entire develop- 

 ment of such a peat-moor can be traced. On the slopes 

 of the Pennines the better drainage will not have ad- 

 mitted of such peat-formation, and, consequently, the 

 original forest has here again been more or less re- 

 established. On many of the limestone r(x;ks, which 



einerge from the peat, a thin layer of this latter is 

 found, and here it may actually be seen in process of 

 formation. The necessary moist basis for the settle- 

 ment of mosses is in these cases given by a layer of blue- 

 green or green Algae of a slimy consistency or by the 

 growth of small Lichens. The mosses grow rapidly 

 and form a thin layer of peat of a dry character, on 

 which a slightly divergent flora is usually developed. 



The above-described method is no doubt not the only 

 way, in which extensive pent-areas may develop, for the 

 silting up of any fair-sized area of water v.ill, given the 

 suitable conditions, lead to the formation of an exten- 

 sive moor, and it is by no m.eans necessary that the 

 silting up should be caused by the destruction of wood- 

 land. There seems, however, no doubt that the Pennine 

 moors owe their origin to such a cause, and it would be 

 no insuperable difficulty to reverse matters and again let 

 forest cover their slopes. At the present day the huge 

 area of peat is quite neglected, and there 

 appears not to be a single peat factorv in the 

 whole district. 



AuMiNii'M does not readily lend itself to 

 plating, because th; plated metal tends 

 quickly to scale off, and the defect has been 

 attributed to the microscopically thin film 

 of oxide which forms on the surface of the 

 aluminium, h new method of dealing with 

 the metal is to immerse it in soluble 

 fluorides, together with some free hydro- 

 fluoric acid ; and thus not only to remove 

 the oxide film but to prepare the surface of 

 the aluminium for the reception of a plate of 

 other metal by roughening its surface. The 

 aluminium is then quickly rinsed and im- 

 mersed in a bath of zinc and aluminium 

 sulphates, and while in the bath a film of 

 zinc is deposited on it by the ordinarj' 

 methods of electro-plating. Other metals 

 may now be plated on the zinc. An 

 electrolytic film of gold will, however, 

 disappear in the zinc, so that if it is re- 

 quired to give a gold plating to the aluminium-zinc sur- 

 face this surface must further be coated with copper. 



The German physicist. Dr. Guillaume, has discovered a 

 new alloy, which he has named Invar. This peculiar 

 product is formed of certain proportions of nickef and 

 steel and has the ability to withstand heat without ex- 

 pansion. When made in a certain way it even con- 

 tracts slightly on being heated. Its importance is easily 

 seen when it is considered that all instruments of pre- 

 cision suffer errors from changes in temperature. 

 Measuring apparatus, and particularly time-pieces, will 

 be greatly benefited ; the ability to make a pendulum 

 certain to stay of a constant length, regardless of 

 thermal influence, will be regarded with enthusiasm by 

 astronomers. Other uses have already been found for 

 it, particularly in surveying apparatus. If it is suffici- 

 ently reliable to replace the ice bars used in triangula- 

 tion work, it would effect a great saving in time and 

 money. 



