July 1, 1899.] 



KNOWLEDGE. 



163 



mosses (Phascum) opening by a decay of their sides, the 

 sporangia of most of the moss on the other hand having a 

 regular dehiscence. 



It is a beautiful sight to see through a microscope the 

 opening of a sporangium of a myxie under the warmth of the 

 sun. We have watched it in the Trichia fallax : sometimes 

 there appears a small hole in the membrane towards the 

 top, which enlarges into a chasm ; sometimes the whole 

 upper part seems lifted or pushed up. Then the closely- 

 packed spores begin to start out — one after the other — 

 falling at varying distances ; then the whole surface of the 

 mass of spores and elaters begins gently to heave and 

 move, and the elaters sway about like the arms of a polype. 

 These actions are, we presume, due partly to the elasticity 

 of the hairs seeking to expand in every direction, and partly 

 to the unequal thickness of the parts of the elaters and the 

 consequently unequal action of the heat on the elaters 

 themselves. They curl and twist because they are un- 

 equally expanded. 



Spores. — The spore is another part of the structure which 

 varies much. Spores vary in size ; they vary in colour, some- 

 times violet or brown, or red or yellow ; they vary in their 

 surface, sometimes smooth, sometimes spinulous or covered 

 with warts ; sometimes covered with a land of network or 

 furnished with a border or band. All these variations are 

 used as points of distinction in the classification of the 

 myxies, and the presence of a dark violet colour in the 

 species is found, as already mentioned, to be of high classi- 

 ficatory value. 



Another curious point about spores is the tendency in 

 some of them to gather into groups of a more or less definite 

 number, whilst others exhibit no such tendency, but remain 

 single or aggregated without law. The spores of Badhamia 

 utricularis have a tendency to gather into groups of from 

 seven to ten, whilst the spores of its nearest congener, 

 Badhamia hijalina, often congregate in numbers as high 

 as twenty, and in other closely allied forms the spores are 

 free. But this character, though generally true, is not 

 absolutely constant. The spores of It. hijalina are some- 

 times almost free, and the same tendency to variation has 

 been observed in other species. 



ELECTRICITY AS AN EXACT SCIENCE. 



By Howard B. Little. 

 IV. — Experience, its Value, and its Danger. 



SINCE electricity has become so great a factor in our 

 daily lives, the experience of every man, woman, 

 and child, throughout every civilized country in 

 the world, has been enormously widened ; or 

 opportunities have been constantly given for such 

 widening. Nor is this all; the far-reaching "fluid" is 

 exercising a distinct influence on the savage. But it is 

 sufiicient for our present purpose merely to note this fact, 

 without entering upon any discussion of it. 



It will not be too much to assert that the popular use of 

 electricity has introduced a new order, or class, of 

 experience. This seems a painfully trite remark when one 

 considers that every business or profession requires its own 

 specially-trained workers ; but what may be termed here 

 "electrical experience" exhibits such a characteristic 

 series of features that its consideration, besides being of 

 interest, should also be profitable. To commence with, 

 the idea of its being possible, by the motion of a relatively 

 tiny lever here, to send messages to the Antipodes, seems 

 to have opened up a new field of thought, which has in a 

 manner been cultivated by the public's reception of such 

 messages here, for the public is straining daily to live at a 

 greater rate, to receive its news more rapidly, and to travel 



faster. To all this it is the electrician's business to attend. 

 As typical instances of the kind of task he should set 

 himself may be mentioned the attainment of a higher 

 speed in signalling, and an increase in the number of 

 messages which, at one time, may be sent through the 

 same line. The latter consideration will, as a rule, resolve 

 itself into a question of maintaining the absolutely syn- 

 chronous motion of two instruments at opposite ends of 

 the line. 



Another point for his consideration is the maintenance 

 of absolute regulation of supply to light and power mains. 

 The question of fuel economy may very well be referred 

 back to the mechanical engineer, because the efficiency of 

 a good dynamo is generally some six or seven times as 

 great as that of a good steam engine ; in fact, as it has so 

 often been pointed out, an enormous percentage of the fuel 

 is wasted between the stoker's shovel and the pulley of 

 the dynamo. 



Unfortunately, man is not endowed with an electrical 

 sense ; he has to rely entirely on experience to ascertain 

 the presence of electricity. And in some instances it is 

 wonderful with what rapidity such experience can be 

 brought into play. To quote a simple instance, and one 

 of every-day occurrence. Suppose a house be "wired" and 

 connected with an alternate-current station. The shock 

 to be obtained from the fuse connections, or any similar 

 points on the circuit, would be quite sufficient to startle 

 anyone unaccustomed to such shocks, and should such 

 an individual be at the time upon a ladder, it is quite 

 possible that he would tumble off. Yet, to the electrician 

 it is nothing, because, brief as the contact would in all 

 probability be, he has yet had time to bring his experience 

 to bear, before giving the involuntary jump. 



Again, it is electrical experience alone which can enable 

 us to rapidly grasp all the details of a system of electrical 

 connections, which may involve the use of dozens or 

 hundreds of connecting wires. And the ideas of self 

 induction and mutual induction seem to the layman a 

 complete upsetting of all his preconceived notions, while 

 he is further appalled to learn that he will have to regard 

 these as existing Ln definite quantities, under definite 

 conditions ; and in consequence subject to mathematical 

 investigation. But, just as some "hyper-mathematical" 

 minds have a conception of a fourth dimension, even so is 

 this amongst electricians, in that to some these quantities 

 assume a far more concrete entity than to others. 



Turning now to quite another class of experience which 

 the electrician must cultivate. He is called upon, more 

 than any other scientist in these times, to explain to the 

 non-scientific pubUc. The less intelligent section of this 

 latter community will, as a rule, be quite satisfied that 

 they thoroughly understand the working of any apparatus 

 if once they have been informed that it is electrical ; and 

 under certain circumstances it becomes the electrician's 

 painful duty to undeceive them, and, with all the tact at 

 his command, to insinuate that they really know nothing 

 whatever about it. On the other hand, there is the indi- 

 vidual who wants to know, and who will ask questions. 

 In this connection the average electrician suffers more than 

 all the members of any Foreign Office ever constituted, 

 for two reasons ; first, he is expected to make clear, to the 

 class of questioner aforesaid, in the course of a few 

 instants, what it may have taken him many years to 

 arrive at a just appreciation and understanding of ; and 

 secondly, because the lay mind, havmg from childhood 

 been familiarized with the phenomena of light, heat, and 

 sound, never reahzes that it has no information whatever 

 as to what they are ; consequently, by sonie curious 

 process of reasoning, or want of reasoning, the impression 



