386 



♦ KNOWLEDGE • 



[May 8, 1885. 



METEOES AND FALLING STAKS. 

 By E.ICUARD A. Proctor. 



(Contiiiued from p. 318.) 



AS to the real change of the velocity or direction of 

 motion which our earth can impart to a meteorite 

 approaching her from interplanetary space, it will be seen 

 from the discussion of the mathematics of meteoric motion 

 which is running on jiari passu with these more popular 

 papers that it may be altogether neglected in comparison 

 with the apparent change due to the earth's rotation. This 

 last only need be considered, and as this must be slight, we 

 see that regarding observed meteors as bodies moving around 

 the sun in orbits of considerable extent, intersecting the 

 orbit of the earth, the constant position of the radiant point 

 on the starsphere, even while the rotational direction 

 changes through a whole right angle can be understood. 

 Moreover the observed fact in this case can only be ex- 

 plained by attiibuting to meteois the rapid motions cor- 

 responding to such orbits. I may note, however, in pass-ing 

 that a change of radiant by more than a degree ought in 

 several cases to take place as the earth's rotation changes 

 the direction of the observer's motion ; and the circum- 

 stance that no such change of radiant has been detected, 

 though it must undoubtedly take place in the case of some 

 meteor systems whose components move in known orbits, 

 and therefore with known velocity, must be remembered 

 later when we are inquiring into the significance of Mr. 

 Denning's discovery. 



The discovery that meteors travel around the sun, led 

 to the recognition of their true orbits in several instances. 

 With this part of the subject of meteoric astronomy I will 

 not at present deal, because I have dealt with it very fully 

 elsewhere. Suffice it to note that it led to the discovery 

 that some meteor systems travel in the orbits of known 

 comets, and to the belief that every meteor system is asso- 

 ciated with some comet, known or unknown, existing now, 

 or long since dissipated (as Biela's comet was recently 

 dissipated) by solar action or other disturbing forces. 



Schiaparelli, to whom this special result was mainly due, 

 though the hardest part of the work of research was done 

 by Prof. J. 0. Adams, was led to a speculation respecting the 

 origin of meteors and comets — viz., that meteor systems or 

 comets are groups of discrete bodies drawn from out the 

 interstellar regions towards our own sjstem, and then com- 

 pelled by planetary perturbations to travel (sometimes) on 

 cloud paths round the sun. 



Since some certainly among the meteor-systems have 

 periods of moderate length, this theory of Schiaparelli's 

 would regard the short-period comets or meteor-systems as 

 drawn out of the interstellar depths, while manifestly it 

 would be absurd not to extend Schiaparelli's theory comets 

 or meteor-systems travelling on non-re-entering paths. In 

 fact, he himself regards his theory as requiring the occa- 

 sional appearance of meteors of hyperbolic path, and there- 

 fore as not merely consistent with the phenomena of 

 hyperbolic comets, but accounting for them. Adopting 

 his theory, then, to its fullest extent, we should regard 

 all comets and meteors as bodies coming from the inter- 

 stellar depths ; for it is not easy to see how any comet or 

 meteor-system could be so far distinguished from its 

 fellows as to be regarded as originally a member of the 

 solar system. 



But for reasons which appear to me incontrovertible, 1 

 find it impossible to give in my adhesion to Schiaparelli's 

 views, in the form in which he has presented them. A 

 line ought to be carefully drawn between what has been 

 proved and what has not been proved respecting the 



opinions which Schiaparelli has advanced. His most happy 

 conception, that meteors would be found to travel in the 

 paths of comets, has been realised, and no possible question 

 can be raised as- to the completeness of the demonstration ; 

 but it is quite otherwise with his supposition respecting the 

 manner in which meteoric systems or comets have been 

 introduced into the solar system. It not only has not been 

 proved that comets have been compelled by the perturba- 

 tions of the planets to become permanent members of the 

 solar system, but it has practically been proved impossible 

 that such an event should occur. 



(To be continued.) 



THE WORKSHOP AT HOME. 



By a Working Man. 



NEARLY all the cheaper furniture that is sold is not 

 made of the wood which apparently forms its 

 material. It is really nothing but deal or beechwood, 

 " veneered." A veneer, I must explain, is a thin sheet 

 of some valuable wood, as thin as a sheet of paper. Those 

 most commonly in u-se are cut from mahogany, rosewood, 

 and waluutwood, and less frequently from bird's-eye maple, 

 and are laid over the finished piece of work in the manner 

 I propose now to describe. Only soft woods can be properly 

 veneered upon, and the amateur is particularly requested 

 to notice that he cannot veneer over a knot. The tools 

 required are sufficiently simple if the surfaces to be 

 veneered are flat. The workman will want, first, a toothing- 

 plane. This is something like Fig. 5, Vol. VI., p. 154, only 

 the iron is very nearly upright, and is fluted with very 

 narrow grooves along its whole width. What this does 

 is really to scratch the wood and veneer, and give them 

 what workmen call a " tooth," to make the glue hold 

 better. A wood file or rasp and a glue-pot we have already, 

 and our remaining needs are a veneering hammer, a sponge, 

 and basin of boiling water, and a laundress's flat-iron. 

 There are two or three forms of veneering-hammer. The 

 massive one used by the professional cabinet-maker is not 

 so easy to work with as the form shown in Fig. 43, in 

 which A represents a side, and B a front, view of the 



Fig. 43. 



hammer. I shall describe the mode of using it 

 immediately. 



Now, the first thing to do is to take the saw-marks out 

 which will probably be visible upon our sheet of veneer 

 when we buy it at the wood-yard. This is done by a fine 

 toothing-plane. If, as is far from unlikely, the beginner 

 should split the veneer, he may mend it by glueiug a 

 piece of brown paper on to what is to be the upper 

 (or out) side of it. In cutting it out, it should rather 

 overlap the surface to be covered. If, which also 

 is likely enough, it should be cockled, it may be 

 damped and left in a screw-press for twelve hours — or, 

 what is the same thing, laid on a flat floor with a board 

 and some heavy weights on the top of it. Sharp scissors, 

 or a penknife guided by a straight-edge, will generally cut 

 veneers to the required shape. 



