QUARTZ FIBERS. 327 



cocoon, aud that filxM' is at the present time carrying a mirror the move- 

 ments of whicli will presently be visible in all i)arts of this large room. 



But that is by no means the limit of the degree of fineness which can 

 be reached. A fiber the fifteen-thousandth of an inch in thickness is 

 quite a strong and conspicuous object. You may go on making them 

 until you can not see them with the naked eye. You may go on follow- 

 ing them with the microscope until you can not see them with the micro- 

 scope — that is to say, you can not find their end, — they gradually go 

 out. The ends are so fine that it is impossible ever to see them in any 

 microscope that can be constructed, not because the microscoi)es are 

 bad, but because of the nature of light. But that is a point upon which 

 I shall not say more this evening. It has been estimated that probably 

 the ends of some of these are as fine as the millionth part of an inch — 

 I do not care whether they are or wlietiior they are not, because they 

 can never be seen and never be used — but certainly the hundred-thou- 

 sandth of an inch is by no means beyond the limit which can be obtained. 

 As these large numbers of hundreds of thousands and millions are 

 figures whicli it is impossible for anybody thoroughly to realize, I may 

 for the purpose of illustration say that if we were to take a i>iece of 

 quartz about as big as a walnut, and if we could draw the whole of that 

 into a thread one hundred-thousandth of an inch in diameter — threads 

 which can certainly be produced — there would be enough to go round 

 the world about six or seven times. 



These quartz fibers, on account of their fineness, are eminently capa- 

 ble of measuring minute forces — that is to say, they would be capable 

 if they were free from that putty like quality which I have described 

 as making spun glass useless. Now, experiments made both in this 

 country and in Australia show that to a most extraordinary degree 

 they are perfectly free from that one fault of spun glass. 



The number of useful i)roperties of quartz that has been melted is so 

 great that 1 can merely take, in a more or less disjointed way, one or 

 two; and I propose, in the first place, to say something which I think 

 may be especially interesting to chemists aud perha[)Sto our president. 

 I should like to ask experimental chemists what they wouhl think of 

 a material wliich could be drawn into tubes, blown into bulbs, joined 

 together in the same way tliat glass is joined, drawn out, attached to 

 a Sprengel pump, sealed off with a Sprengel vacuum which wouhl be 

 transi)arent, wliicli would be less acted upon than glass by corrosive 

 chemicals, and which finally at the point at which platinum is as fiuid 

 as water would still retain its form. Here is such a tube with a bull) 

 blown at the end. T have found that it is possible to make tubes 

 (though it can not be done in the ordinary way as with glass) and to 

 blow bulbs with quartz, and that they have this advantage which glass 

 does not possess, namely, that it is almost impossible to crack them 

 by the sudden api)lication of heat. 



Then there is another property which (juartz fibers an<l rods possess 



