Jan. 12, 1883.] 



KNOWLEDGE 



27 



troscopic values for each day ; this would be likely to help and 

 encoura<re other observers. 



Another question 1 wish to ask is, can you or any of your readers 

 give nie information respecting a fossil gum found in New Zealand, 

 and called there " Kawrie." A cousin of mine just returned from 

 New Zealand tells mo it is dug up from 6 in. to 20 ft. below the 

 surface (in the North Island). It varies in colour to from nearly a 

 pure crystal to beeswax. I have had some dissolved in chloroform 

 and ether, to use in mounting microscopical objects ; it is (piito as 

 clear as Canada balsam. Some of the wood (the tree still grows, I 

 believe, only in the North Island) I have examined in thin sections 

 under the microscope. It shows the peculiar glandular discs of the 

 conifers, but in an arrangement I do not remember seeing before 

 in such woods. Joseph Claek. 



EARTHQUAKES IN WESTMORELAND. 



[080] — A smart shock of earthquake was felt in Westmoreland 

 in 1835, which has not been referred to in your notices of Earth- 

 quakes in the British Isles, and as I still retain a very vivid im- 

 pression of it, I, venture to offer the following particulars. It 

 occurred about the middle of August. I was on a visit at a friend's 

 house. The night had been so excessively sultry it was almost 

 impossible to sleep, and soon after sun-rise I was startled by a loud, 

 rattling, and rumbling noise, which at the moment I thought was 

 occasioned by a team of horses running away with a heavy waggon 

 over a rough road. Immediately afterwards the glass and earthen- 

 ware in the room were violently sh.iken, and I distinctly recollect 

 the lateral motion was so strong that, lying on the edge of the bed 

 on account of the heat, I was very nearly thrown on the floor. On 

 looking out of the window, the cattle in the park were seen rushing 

 wildly about with signs of great terror. I do not remember whether 

 any buildings were injured, but the arch of a small bridge was dis- 

 placed and partly inverted. I think there was only one shock, and 

 it seemed to come from the sonth-west. 



Dec. 18, 1882. Matthew IJKi.r,. 



LONGEVITY OF THE DOVE. 



[6871— A Turtle Dove* died at East Keal, 24th October, 1882, 

 aged 15 years. The bird was given to the son of one of his tenants 

 at Crowland by a gentleman still living at Bedford, in the year 

 1852, having been in his possession 15 years. Since then it has lived 

 without a mate 8 years at Crowland, 20 jears at Aswardby, and 2 

 j-ears at Keal. 1 have kl]0^^•n it myself during the last 20 years of 

 its life, and believe the above f.icts can be authenticated. 



Horncastle, Oct. 28, 1882. C. J. CAswKir.. 



anstorrs; to Coritsponlients* 



S. N. N. (1) notes that, like our correspondent in No. 55, ho 

 often, when tired, writes " b " for " p," " d " for " t," " v " for " f," 

 confusing no other letters. 2. Italian. — H. B. Heath. You are 

 right and wrong. The sign Y' is for the Siyn of the Ram ; but 

 owing to precession the sign and the constellation no longer agree. 

 The sign Aries is now in Pisces. — Taranaki. (1) Please de- 

 scribe your mechanical method for trisecting an angle. (2) It 

 would be impossible to explain ihe instrument without seeing it. — 

 W. C. P. (M.A. Oxon.) Many thanks for suggestions, which I care- 

 fully note.— R. C. N. Many tlianks. But readers object to more si)ace 

 being given to Mr. Siemens' thcon- ; and as yon evidently recognise its 

 insufficiency, no adequate purpose would be fulfilled by printing 

 your paper maintaining that some of the objections are not valid. 

 But tirst, in reply to your question, Why should the substances 

 compounded with evolution of light and heat as they approach the 

 sun, fall on his surface, as 31. Him suggests ? I would apk. 

 Where is the light evolved ? Is it not at the surface ? Secondly, 

 if the interstellar air is thinned to the degree you mention, it is 

 hopelessly inadequate to do what either Mr. Siemens or Mr. 

 Williams wants. (Compared with air's, its density you give as 

 a fraction having a single digit in its nnmcrator, and .350 

 digits in its denominator.) Thirdly, to calculate the effect of solar 

 globe rotating in a space universally pervaded by an atmosphere, 

 is not quite so simple as some seem to imagine. The outer parts of 

 the rotating body merging into that atmosphere, we should want to 

 know the am< unt of frictionnl resistance, and to remember that 

 while the frictional action of air on air gives the centrifugal tend- 

 ency, the motion (thus produced) of air in air would presumably 



* A small terra-cotta-coloured bird with a black ring round the 

 back of the neck. 



be frictionally resisted too. If the sun were not himself moving in 

 space, a steady current might, perhai>s, after a while, be produced ; 

 but how far it would extend is another matter. The sun, however, 

 is not at rest, and this brings us to another very serious difficulty : 

 if !such effects as Jlr. Siemens' thcoi-y requires are produced by the 

 motion of the exterior ]iarts of the sun's equator at the rate of. say, 

 100,000 miles a day, what would bo the effect of the sun's motion 

 of translation at the rate of more than 400,000 miles a day — sup- 

 posing Otto Strnve's estimate not to fall short (as I believe it does 

 in enormous degree) of the true velocity. — G. T. R\tes. (1) Sir J. 

 Uerschel's "Lectures and Essays," published by Strahan, and, I 

 think, also by Routledge. (2) Pardon me ; you were not told that 

 the comet would return in six or seven months, but that if a certain 

 observation telegraphed from the Vienna Observatory were trust- 

 worthy, that would hapjien. The observation was incorrect. It 

 misled others besides me. Theoretically, three observations of a 

 comet lix its orbit ; but unfortunately the nucleus is neither a 

 circular disc nor a point ; hence tho real position of whatever point 

 is tho true centre of tho comet's mass is not readily determined, 

 A verv slight error on this point would nuiko a wide difference 

 in our estimate of the comet's orbit, from throe, or even from 

 a dozen, observations. Sad, indeed, [if "public confidence in the 

 calculations of astronomers should be shaken for a long time 

 to come," If astronomers made comets to order, their failure to 

 make them with nice-shaped nuclei would be blameworthy. But 

 thev don't. I rather fancy my own error was due to a careless 

 telegraphist than to the observers at Vienna. (3.) Many talked 

 about Swift's moons of Mars at the time when tho real moons were 

 discovered. The idea was jirobably Arbuthnot's, as Swift would 

 not have worked in Kepler's Laws, But the suggestion that Mars 

 should have two moons is much older. It was first thrown out 

 by Kepler in a letter to Galileo on the discovery of the four 

 moons of Jupiter. Kepler, also, was the first to throw out 

 the idea that planets invisible to the naked eye travel between 

 Mars and Jupiter. — C. J. Buow.v. Mr. Dallinger's article 

 puts it well, you think : well, as it claims infinity of ex- 

 cellence, it could hardly go much farther. He sees no " ragged- 

 ness and inferiority" in those Eastern books. When, glancing over 

 his columns, I supposed he was speaking of all such books, I 

 thought he put the matter pretty fairly. Only I thought he omitted 

 to make adequate reference to certain iniquities. The system on 

 which Caliph Haroun al Raschid distributed justice may bo very 

 attractive to Eastern minds j but neither his plan of apportioning 

 punishment to the innocent (as the members of an offender's 

 familv), nor his way of condoning offences, accords with Western 

 ideas'of justice, or even of morality. Some may, perhaps, find in 

 this injustice, multiplied by infinity, something infinitely adorable: 

 I cannot, I can imagine men crouching in terror before such a 

 power, but not revering it. Mr, Dallinger seems quite to mis- 

 understand the agnosticism of modern science. It does agree 

 with the snying of old, " As touching the Almighty, we cannot find 

 Him out ; " but while it may, nay must, be in darkness as to what 

 the Almighty i/^, it entertains no manner of doubt as to what He is 

 not. You may rest well assured that with whatever zeal and 

 warmth believers in any special dogma denounce scientific teachings 

 which they may regard as inconsistent with it, the student of the 

 Laws of Nature rejects with at least equal earnestness the doctrine 

 that the God of Nature is the Brobdingnagian Bashaw imagined 

 by Eastern, and idolised by many Western, minds. Hero Sense 

 and Science alike aro on sure ground. The existence of evil, the 

 sufferings of the innocent (men and brntes alike), and other such 

 troubles, may perplex and puzzle science, as of old they perplexed Job 

 and his friends : but they will never lead Science to accept Infinite 

 Iniquitj- as Deity, any more than they led Job to " Curse God and 

 die," 



ELECTRICAL, 

 G. F, 1. If a continuous wire be wound so as to have a right- 

 handed helix on one end of tho bar, and a left-handed on 

 the other, the passage of a current will develop similar poles at the 

 two extremities, and tho inner ends of the two coils will conspire 

 to make a strong i)olo in the centre, because a current leavimj u 

 riijht-handed helix has the same inductive effect as it would have 

 on enteriit'j a left-hatided helix. (2) No. If two unequal positive 

 currents attempt to enter a wire at its opposite extremities, the 

 only current that will show itself will be tho difference between 

 them. If they .are equal, neutrality results. If they arc opposite, 

 they conjointly produce a greater effect than would either current 

 by itself. In the latter instance, however, the two opposite currents 

 in 0|)posite directions should be regarded as tho sarao current 

 flowing in one direction, (3) Tho original armature already 

 described in " Amatem- Electrician." Tho pre.^ent modified form 

 adopted for large dynamos consists of a long cylindrical drum, on 

 which are wound several independent coils of wire attached to the 

 commutator simUarly to the Gramme. 



