,Ian. 



1882.1 



• KNOWLEDGE • 



271 



rarntioned acid, aloiip with carbonate of soda and glucose" is 

 I Inted. "The dcsif.'n is siarcolv visible at first, all the Hubstances 



!i;4 colom-loss. But if the cloth is exposed for two miimu-s to a 

 ■i\|>erature bordering on 100° C the design appears, and the fonna- 

 !i of indigotine (i.e. pure indigo) is so plentiful that the colour 

 i.rars black. Washing with water removes tho soluble matter, 



i indigo blue becomes visible with all its characters, and is inti- 

 itelj- fixed upon the fibre." Although tho manufacture of this 



•resting compound has been, according to the Tfxtile Manu- 

 ■t'lrer, given up bv one Continental factory, it undoubtedly only 

 mains a matter of time for the further and more practical develop- 



nt of this new industry, and most probably it will become as 



ccssful a competitor with the natural product as alizarine is with 

 idder, the cultivation of which has almost ceased, the beet being 

 Uivatcd in its place for the manufacture of sugar. 



V 



.SCIENCE AND RELIGION. 



CflKRESPONDEXT writes :— " I find fault with the seeming 



tendency of science to account for all 'physical' and 



emical ' laws as being merely due to ceitaiu fixed laws of nature. 



- iontific men may say that by natiue they really mean God, 



that nature was made by God ; but the fact remains, tliat 



ose who learn may or will say Nature does everything her- 



If. there's no need for a God. Lectm-ers are too fond of 



■!i words as the following: 'These are the means by which 



uure works. In this case Natm-e adopts such and such a 



uisc." When some weak-minded people (and there are many snch) 



■ constantly hearing the one refrain of the whole law of existence, 



ing merely a question of 'chemical' decay and 'chemical re- 



roiluction,' they say there is no God but these; they will per- 



• hance ask the question — "Was there ever any beginning ? Will 



■ lii're ever be any end ':' ' One of our great men made use of the 



■v urds that man was nothing but a ' shovelful of pliosphates.' 



-icli words spread quickly, not for good but for much evil. These, 



r, are the points to wliich I would draw attention. I, for 



1 •• would gladly .^ee a really good correspondence anent this 



litter. Yet even in this case, I would fear that some of the argu- 



I .iits advanced on the side of science would cause much mischief 



iHingst those of weak minds or weak faith." 



We receive so many letters of this kind, that we think it well 



■ admit so much as we have tiuoted of our correspondent's letter 

 il that is essential to the argument has been left) ; but it is only 



ll'iwed to a])pear 'as the Helots were allowed by the Spartans to 

 low the bad effects of indulsrence. To the kind of correspondence 

 'lich our correspondent invited (yet deprecates, thougli seeking to 

 litiate it) our columns are emphatically not open. We can neither 

 itler scientific facts to be advanced as oppugning nor as sui>- 

 •rting specific religious doctrines. If scientific statements were 

 iide here which seem, whether to "those of weak mind or 

 1 iF?eak faith," or to able reasoners, to be oi)posed to rcli- 

 i'us doctrines which they hold, our correspondence columns 

 "aid be open to scientific objections to such statements. Tuey 

 add be open to letters showing how such statements may 



■ i-cconciled with the religious doctrines apparently oi)pugued, 

 ithey were open to suggestions on the other side. But the 



' ilance will be held fairly so far as lies in our power. We 

 ,'ard the wider questions of natural religion as within onr scope, 

 It ihose who wisli to attack specific religious opinions from the 

 ie of science must seek some other arena ; and so also must those 

 lio wish to attack science from the side of religion. Onr purpose 



■ 10 is to seek for scientific truth. We are in no way concerned 

 Ith the religious tenets of our contributors or correspondents. 

 iiose, on the one hand, who are unsati.sfiod with science unless 



..-cd as a weapon wherewith to attack religious opponents; and 

 those, on the other, who ask, first, not whether a scientific 

 statement is true, but whether it Qan be reconciled with their 

 religious views, will find science, as treated in those pages, alto- 

 gether unsatisfactory to them. If there are few who do not belong 

 either to one category or to the other, we shall have to admit that 

 Knowledge is a mistake. But we should not change cur plan ; we 

 should simply abandon our purpose. — Ed.] 



Separate Soixds ox One W'ire. — JI. Slaiche lias found by ex- 

 periment that sounds of diffei-ent characters produced from two 

 separate sources can be sent simultaneously on one wire and rec.ived 

 , separately. Ue used at the receiving station two telephones of 

 different resistances, and at the transmitting station caused a musi- 

 cal box to be set going on a microphone of small resistance, while 

 an induction telephone transmitter was spoken into at the same 

 time. The musical sounds were reproduced in the telephone which 

 had tho least resistance, and the vocal sounds in the other, so that 



with the two telephones to tlie ears, the music could be heard by one 

 ear and tho speech by the other. — Scientific American. 



The FiiENCii Sociat, Probi-em.— At the beginning of tho present 

 century, with a population of not more than twenty-seven millions, 

 there were actually more births in France than took place m the 

 year ISiSO. M. Legrand, in his well-known essay on " Lo Manage 

 et les Mceurs en France," states that between 1800 and 18I.> the 

 number of children bom per marriage averaged 4-21- ; since then ii 

 had sunk graduallv. and in 1860 averaged only 30;i for the five lire- 

 ceding vears. It rose again nntil 1805, but has since declined ; and 

 in the'year 1871, the date of tho Franco-German War, reached its 

 lowest "depth of 2-26. In 1872 the average rose to its highest for 

 the last few years, namely 267, and in 1877 it was 255. M. Legrand 

 asserts, on the strongest possible gi-ounds, that this decrease in the 

 birth-rate of his countiy continues, and is becoming more marked 

 as the years go bv. It is a noteworthy and, perhajis, ominous fact, 

 that lately the number of mai-riages have not decreased. Indeed, 

 there are actually more marriages per cent, in France than in 

 England, the average per hundred being in the former "SS, and in tho 

 latfer -86. 



Asbestos Fire-pkoof Paixt. — A series of interesting experiments 

 on a practical scale were recently carried out in tho grounds of tho 

 Crystal Palace with asbestos paint, in order to test its qualities as 

 a protective covering against tire. This paint is a new and special 

 preparation of asbestos, and is being introduced by the United 

 Asbestos Company, of 161, Queen Victoria-street, E.C. The asbestos 

 in a finely divided state is mixed with a fluid material, and is used in 

 a similar manner to other paints. Unlike them, however, it is 

 uninflammable, and not only .so, but is capable of communicating 

 this valuable attribute to such substances as it may bo applied to. 

 This applies alike to cotton fabrics and to timber or other in- 

 flammable materials used for constructive or decorative 

 purposes. Hence its great value in connection with theatrical 

 properties and appliances, especially those connected with the 

 statre arrangements. It was to demonstrate this valuable feature 

 that the experiments were carried out, in the presence of the 

 Lord Mayor and Lady Mayoress, the representative of the Lord 

 Chamberiain, Captain Shaw, and a number of other ladies and 

 gentlemen who had been specially inWted, besides the visitors 

 at the Palace generallv. The first experiment consisted in 

 submitting to the action of fire some linen, cotton, and 

 r^auze fabrics which had been partially treated with the paint 

 On setting fire to them, the unprotected portions quickly blazed 

 awav into tinder, the protected parts remaining intact. The ne.xt 

 exiie'riment consisted in placing on one part of a fierce fire some 

 blocks of wood painted with asbestos paint, and on another part 

 similar blocks of wood not painted. In the course of a short time 

 the unpaintcd blocks were entirely consumed, while those which 

 were painted resisted the action of fire for a long time without 

 sho«Hn<' sitnis of deterioration. At length, however, the fierce heat 

 of the fire raised some blisters, which on bursting admitted the 

 intense heat, which charred the wood, the extenial coating of paint, 

 however, being greativ preserved. In the final experiments, 

 four timber erections were employed, two being about 1- tt. 

 wide bv 8ft. deep and 10ft. high, and representing theatrical stages, 

 with ropes, curtains, and effects. Tho other two were open timber 

 sheds, about 6 ft. square in plan and 8 ft. high. One of each of 

 these tw.) classes of structures was protected with the asbestos 

 paint, tho other two being of plain timber. Piles of shavings 

 and other inflammable materials were placed under and upon 

 tlie floor of each strtictuie, and lights were applied to nil 

 simultaneously. The unprotected stage qiuckly caught tire, 

 and iu about twelve minutes it was a heap of blazing rums. 

 The unprotected shed, being open-sided, did not take fire so 

 soon nor burn so rapidly, but the flames eventually got hold 

 of it. Both the protected stage and shell resisted the effects ot 

 fire to the end most successfully, although infiamuiablo materials, 

 including naphtha, were occasionally employed. In the course of 

 half-au-hour some portions of the fittings were found to be 

 smouldering away, but at no time was there any outburst of fl.ame 

 from the protected materials. The interior of the woodwork, ho^y- 

 ever, was well blistered, bat the wonder is that it ehowi-d so little 

 evidence of damage. The gauze and lighter fabrics disappeared at 

 an early stage, but only by crumbling gradually away in an mean- 

 descent condition, and never once by bursting into Hame. These 

 results are highly satisfactory, and fully demonstrate tho value ot 

 the asbestos paint as a fire-resisting medium in respect of its 

 application to theatrical stages and effects, or, in fact, to any other 

 structures or their fittings. On returning to the jialaco after t he 

 cxiieriments the visitors were gratified by a private view of the 

 concert-room, which was beautifully illuminated for the first time 

 by the Edison electric light. The demonstration was distinctly not 

 a public one, but was only the engineer's experimental trial of the 

 engines and Edison machines, which have just been pot in position. 



