April, igo6.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



401 



lithic st.Tife, parti)' of very complete development. Even the 

 remarkably perfect pieces which are occasionally found 

 among' eoliths have their parallels at Mantes, where there 

 occur scrapers, hollow scrapers {lames d encachcs), and borers, 

 which recall the finished types of La Madeleine. Bulbs of 

 percussion, secondary chipping, and the other so-called 

 criteria of intentional workmanship are all represented in 

 their turn ; and this is the more remarkable because the 

 flint of Mantes is dry and hard of fracture. Were the softer 

 Hint of Puy Courny, for example, placed in the machine, 

 we might expect modifications which differ from those ap- 

 pearing in the more refractory material obtained from the 

 chalk. 



" The process of manufacturing eoliths at Mantes is a 

 rapid one. Recent experiments have shown me that they 

 can be produced after a few hours of the rotary motion in 

 water. When the tub is emptied after the lapse of twenty- 

 nine hours the condition of the flints suggests the following 

 sequence of events. Those first affected assume eolithic 

 forms and are subsequently rolled and worn ; at a later stage 

 some of them are subjected to further shocks which give 

 them the appearance of re-worked implements ; in this con- 

 dition they would resemble later (re-worked) eoliths. In anv 

 case it is demonstrated that the cement tubs of Mantes pro- 

 duce eoliths which are astonishingly like those of geological 

 formation. As I showed in my previous paper, the arrange- 

 ment of the machine proves that the pseudo-eoliths are 

 chipped, not by an\' part of the mechanism, but bv the shock 

 and pressure of one flint against another. The rapid action 

 of the water resembles that of the Rhone, Rhine, and other 

 rivers when in flood, while smaller streams would be still 

 more impetu^us. The pot-holes formed by rivers are known 

 to every student of geology. Anyone who has ever studied 

 the ancient gravels of the Seine or Somme and other rivers, 

 will be readily convinced that their volume was once very 

 different from that which we now see. To-day they can 

 scarcely carry down pebbles of small size, but formerly they 

 deposited strata of the coarsest gravel, containing rolled 

 blocks exceeding a metre in diameter. .Ml this presupposes 

 a torrential river-action such as no longer exists in these 

 regions at the present day, but was experimentally repro- 

 duced at Mantes." 



Few people could readily say which of all animals was 

 the most conservative, but an article by Dr. E. H. 

 Scllard in the Popular Science Monthly enables us to 

 award the palm to the cockroach. No insects are more 

 abundant as fo.ssils and none so widely distributed 

 through the various formations as are the cockroaches. 

 The domestic cockroach, as many of us are aware, has a 

 predilection for the neighbourhood of the kitchen boiler. 

 The reason for it is that throughout geological time it 

 has delighted in moist places. TTiey are often found 

 near the traces of streams; usually embedded among the 

 remains of fossil ferns; and, indeed, persistent search 

 among fossil leaves of land origin will hardlv ever fail to 

 bring to light at least detached wings and perhaps 

 bodies of prehistoric cockroaches. It is an approxi- 

 mately coinpletc geological record, an almost undam- 

 aged genealogical tree, which lends an especial interest 

 to the cockroach family. Throughout their long exist- 

 ence they have retained, as compared with other 

 insects, a relatively generalised structure. Morpho- 

 logically they have learnt nothing, and have forgotten 

 nothing. There have been one or two changes in their 

 strnrlure since Paheozoic days. Their heads became 

 tlatleiicd; the upper part of theirchests, the first thoracic 

 segment, became rounded in the carboniferous era. The 

 wings also began to change in the time of the coal 

 measures, and the modern cockroach shows an altera- 

 tion of the wing dating from Permian days and develop- 

 ing since. Hut except that the adventurous spirit and 

 probably the fig-hting ability of the early days, as 

 marked by stronger wings and bigger bodies, have 

 decayed, the cockroach to-day is about exactly what it 

 always has been. 



A Simple Gas-Lighter. 



By Charles E. Benh.am. 



The following simple device will be found very conveni- 

 ent for gas lighting, especially where incandescent 

 mantles are used. 



,\ celluloid tube — the tube of a cycle pump is exactly 

 the thing, and at the cycle shops there are always w'orn 

 out pumps to be had for a few pence — is fixed vertically 

 in a wooden socket. At the upper end is inserted, so 

 as to line the upper part of the tube, a wooden rod 

 covered with tinfoil and about six inches in length. 

 The rod is surmounted by a metal ball, which rests on 

 the top of the celluloid tube. From the ball a thin wire 

 is led to a thick iron wire projecting from the wall to a 

 point centrally over the gas chimney. This iron wire 

 must be insulated from the wall by a vulcanite or glass 

 support. A second iron wire, uninsulated, also pro- 

 jects from the wall and terminates at a point about one- 

 tenth of an inch from the first. 



A strip of celluloid — such as a photographic celluloid 

 film with the gelatine removed — clasps the celluloid 

 tube by means of two little strips of wood, glued to it 



P3} 



A Simple Gas- Lighter. 



as shown, and screwed together when the encircling 

 film has been drawn tight round the tube. The film so 

 forms a rubber which, when held by the wooden strips, 

 can be passed up and down the celluloid tube. At every 

 movement up and down of the rubber, sparks fly be- 

 tween the terminals, and the gas lights instantly. The 

 finger and thumb should nip the rublx.'r in the centre so 

 that it presses close to the tube. The arrangement is 

 not materially affected by atmospheric conditions. A 

 curious feature of the device, and one which at first 

 sight appears to be unorthodox, is the circumstance that 

 tlic rubber and the electric to be excited are both of the 

 same material, instead of being of differeiit materials 

 as is usually the case with friction machines." A rubber 

 of flannel or silk may, however, be used instead of the 

 celluloid film. 



The moiuilod celluloid tube can be aflixed either 

 \erticallv on a shelf below the gas bracket or projecting 

 horizontally from the wall, as may be the more conveni- 

 <'nt arrangement. 



■|"he terminals should not be pointed, but shoidd be 

 formed by loops at the ends of the thick wires, which 

 are to be adjusted so that the spark is about an inch 

 above the top of the gas chimney. The tube should 

 prrferablv Ije of vi-hite celluloid. I'sing a larger cellu- 

 loid tube a Geissler tube may be beautifully illuminated 

 by connecting it with the brass ball. 



