380 



KNOWLI^DGE. 



October. 1912. 



till' circumfLTcncc of the arc, sudi as H X, S(j tliat 

 all the noise reaches the observer in a small fraction 

 of a second, a shorter period, even, than in such a 

 case as that of Figure 41iS. Loudness is, of course, 

 due in some cases to the flash being very near, say 

 within a few hundred feet, when the nearness of the 

 nearest part of it makes up for a necessarily fairly 

 long '• jieriod of total arrival." 



The Gold .'\nd Sii.vkk Shiicld. 



In comparing accounts which different persons 

 give of the same occurrence, the very diversity which 

 is sometimes so informing to the expert merely 

 serves to mystify those who have not studied the 

 principles which dominate such occurrences. This 

 is especially true of natural phenomena, with respect 

 to which differences of position and of distance are 

 not always accorded the consideration which thev 

 demand. Two witnesses may differ, and both be 

 right. A very striking example of this is furnished 

 by F'igure 423. Leaving out of consideration the 

 dotted flash from H to O, let us fix our attention on 

 the flash from H to P. Suppose that this flash 

 struck a factory and did much damage, at exactly 

 eight o'clock in the evening. At a quarter to eight, 

 near the place marked Y, a man was, let us sujipose, 

 found murdered, just dying from a recent wound 

 inflicted by a knife belonging to Tom Cornseed. a 

 man employed on the farm at .\. This man usually 

 leaves the farm at about seven o'clock to walk to his 

 home near Y. Some other circumstances point to 

 his guilt, but two reliable witnesses swear that he 

 was at the farm. A, till the bi^ flash of li,i;htiiiii}< tlnit 

 struck the factory. These witnesses had nowatciies. 

 and the usual work of the farm had been disturbed 

 by the storm, which had also made the evening 

 unusually dark. Their only know ledge of the time, 

 with any accuracy, is that afforded by the great 

 flash. This they describe as very bright, and follow ed 

 by a loud peal, but not followed by a very sharp 

 crack. .\ witness at Y, having an accurate watch, 

 describes the stroke at eight o'clock as being follow ed 

 by one of the sharpest and loudest cracks he ever 

 heard. The two farm witnesses, re-examined, 

 waver in their evidence, but under cross-examination 

 go back to their first statement and hold to it 

 doggedly. Is the man Tom Cornseed to be hanged ? 



It dei)ends upon whetlier anyone concerned is alive 

 to the fact that the evidence is not conflicting, and 

 is able to convince the judge and jury of this fact. 

 What would a capable assessor do ? He would first 

 point out that the observer at Y, though the same 

 distance from P as those at the farm A, might be, 

 as in P'igure 423, some one thousand feet or so nearer 

 to the flash, on the average. He would then show, 

 from Figure 423, how the point P might be only 

 some four hundred and twenty feet further from Y 

 than the point H, while the difference between the 

 distance of P and H from A is one thousand seven 

 hundred and forty feet. The " period of total 

 arrival " at A is, therefore, more than four times that 

 at the point Y, which accounts for the noise being 

 less loud. So far the evidence is shown to be not 

 necessarily in conflict with that by the witness at Y. 

 If, now, the assessor can find witnesses from a 

 mile or so awa\% to either side, or both sides, whose 

 evidence shows that the flash did start as in Figure 

 423, then the evidence of the farm people is shown 

 to be in accordance with probability and is all the 

 more likely to be reliable. 



THK PoSHK AM) THE IXTERPRETKK. 



It is a remarkable fact — probably due to the 

 arrogance of a certain t\-pe of person who calls him- 

 self a " scientist " — that a very large number of 

 persons set their faces resolutely against the accept- 

 ance of explanations of natural occurrences. The 

 same persons will accept without question the state- 

 ment that Mr. Edison has invented an electrical 

 storage battery which will revolutionize all aiipliea- 

 tions of power ; or that one Tcsla, has found out 

 how to communicate, electrically of course, w ith the 

 planets. The}' cannot believe, however, that an 

 ordinary person who neither wears spectacles nor 

 smokes strong cigars can possibly be able to 

 explain how the tides occur, or why the light- 

 ning speaks sometimes with an explosive crack, 

 sometimes with a rending crash, and some- 

 times with a loud peal which, repeated from 

 many clouds, reaches when the distance is too 

 great for us to hear the noise of the flash itself. 

 Yet we make many mistakes because, in probing 

 into the future, we fail correctly to interpret the 

 present. 



NOTICES. 



EARLY MICROSCOPES. — In Hull Museum a serious 

 attempt is being made to illustrate the growth and evolution 

 of various exhibits, whether they be spinning wheels, bicycles, 

 lighting appliances, or corsets, and an opportunity having 

 recently occurred of showing a series of instruments bearing 

 on the development of the microscope. Mr. T. Sheppard. the 

 Curator, describes them in the .August number of The 

 Xaturalist. The paper is illustrated, and the figures 

 show specimens ranging from the " screw barrel " microscope 

 held in the hand and used about the year 1 725 to a more 

 imposing one dated 1780. The latter is of interest because it 

 belonged to Charles Sherboni, who lived from 1796 to 1838, 

 to the late Charles William Sherborn, who died in 1912. and 

 was presented to the Museum by Mr. Charles Oavies 

 Sherborn and his brother, Sidney Newton Sherborn. 



WASPS REMOVING FROM THEIR NEST.— Mr. 

 J. Edmund Clark, of Purley, sends the following interesting 

 note to The Gardeners' Chronicle for August Jlst. A 

 powerful nest of wasps established itself among the .-Mpines 

 last July in the garden of Mr. H. T. Mennell. Park Hill Rise. 

 Croydon. One afternoon, as hundreds of the insects were 

 flying in and out. Mr. Mennell and his daughter stood within 

 two yards for some while, unmolested and unmolesting. They 

 decided to treat the nest that night with boiling water and 

 paratTm oil. for it was in level ground. Coming back a quarter 

 of an hour later, they were astonished to find the wasps busier 

 than ever, but all flying off in one direction over a fence, laden 

 with eggs, grubs and pieces of the nest. In about an hour the 

 place was practically deserted, as it has remained to date 

 UAugust 22nd), though the hole has not been touched. 



