10 



♦ KNOWLEDGE ♦ 



fJoLT 6, 1883. 



degrees of accuracy during the whole period I have known her. 

 Occasionally her rapid and precise perception, or, if you prefer the 

 word, conception, of the picture, and of the many, yet minute and 

 trifling, objects going to form its entirety, is really startling. I 

 have but seldom seen her wholly at fault, though she has met with 

 her failures. 



Now, this seems to us a much more marvellous power 

 than that of thought-reading ; but this is not all Mrs. 

 CroacI appears to have had the very power which Mr. 

 Bishop attributes to himself, in a very much higher 

 degree : — 



Sitting quietly by, or near to, Mrs. Croad, my attention has been 

 again and again rivetted on the manner in which Miss Croad holds 

 communion with her mother. Miss Croad does very certainly move 

 her fingers over and about the face of her mother, but few, if any 

 letters or words are formed by her. Watching her very narrowly, on 

 several occasions, I felt at length assured that Miss Croad's com- 

 munications were altogether unlike those made by either visitors or 

 friends. The latter named formed letters, and \vith these words, 

 and so conversed — if the expression be allowed — with Mrs. Croad ; 

 but it is not so with her daughter. Impressed with the fact as above 

 stated, I spoke to Miss Croad of it, when she told me that as the 

 rule it was requisite simply that she put herself in a close or per- 

 sonal contact with her mother to convey to her what was wished, or 

 to give her a knowledge of this or that, as the case may be. Now, 

 so marked a mental sympathy or concordance as this is altogether 

 without or outside the experience of most of us ; and it is therefore 

 well worthy the attention of those present who have the cotu'age to 



investigate, what I may well call, unorthodox medicine As 



a ftirther illustration of Mrs. Croad's peculiar and clairvoyant gifts, 

 it should be stated that at my second interview w-ith Mrs. Croad, 

 and in the presence of Dr. Andrews and others, certain of my own 

 personal and private convictions on a particular subject became, 

 as it would seem, in a strange and exceptional manner, known to 

 Mrs. Croad. She asked me if I would allow her to tell me a secret 

 in my own life-history, and would I be offended if she wrote it oa 

 her slate. I replied, " No." That written on the slate was and is 

 a fact, than which nothing could or can be more truthf til and to the 

 point. Dr. Andrews is prepared to verify this ; the others present 

 on this occasion were but little known to me. 



Here we have one of the most remarkable amongst 

 numbers of instances of thought-reading, known to all 

 students of the more abnormal facts of psychology — an 

 instance encountered by steady-going professional men, in 

 the ordinary course of their profession, and never produced 

 on platforms for the amusement of the crowd at all. Dr. 

 Carpenter, in his remarkable work on "Mental Physiology," 

 has admitted the probability of the existence of some such 

 power as this, on the evidence in his own possession ; indeed, 

 Mr. Bishop declares that Dr. Carpenter has verified the real 

 existence of some kind and degree of this power in Mr. Bishop 

 himself, and has stated his belief that Mr. Bishop's powers 

 have been tested under strictly scientific conditions. Now, 

 we do not pretend to have any specific opinion of our own 

 upon Mr. Bishop's case, and have absolutely no right to 

 any such opinion. iSTothing is more marvellous than the 

 assumption of a mere man of the world like Mr. Labouchere, 

 that because the phenomena have never come within his 

 knowledge, they are incredible. To him, apparently, 

 opinions like Dr. Carpenter's are not even entitled to a 

 respectful recognition, for he does not refer to them, unless 

 it be in the remark that " nonsense dies hard." At all 

 events incredulity dies hard. There are plenty of facts on 

 which eminent medical men have come without having any 

 motive whatever for credulity, and to which they have 

 been compelled to give their attestation, such, for instance, 

 as those we have quoted from Dr. Davey's address to the 

 Bath and Bristol Branch of the Medical Association, far 

 more remarkable, and far more difficult to bring under any 

 of the known laws of nature, than the achievements of Mr. 

 Bishop, even if these achievements be what Colonel Statham 

 and Colonel Trench affirm, and what Mr. Labouchere 

 denies. — Spectator 



FLIGHT OF A VERTICAL MISSILE. 



By Richard A. Proctor. 



Let a b be part of the earth's equator, C the earth's 

 centre, and let a missile he projected in direction a k {ver- 

 tical), v)ith a velocity of 1,000^1!. p«r second. Supposing 

 the point a to he carried to c durint/ the flight of the missile, 

 determine the point, b, where the missile will reach the 

 ground — in other words, determine b c the westerly devia- 

 tion of the missile. (The resistance of the air is neglected.) 



Let aA.h be the actual path of 

 the missile, and part of a long 

 ellipse AA' about C as farther 

 focus, the portion aA.h being ap- 

 preciably parabolic. Join Ca, Qb, 

 Cc, and draw AM to bisection of 

 arc ah. Then, by Kepler's second 

 law, the missile in moving around 

 the path aAb, sweeps out equal 

 areas around C ; and ob\-iously the 

 point a sweeps out equal areas 

 around 0, as it is carried uni- 

 formly along the arc ahc. More- 

 over, it is clear that the missile 

 as it starts from a and the point 

 a in passing from its initial posi- 

 tion a are sweeping out the same 

 equal areas around C (for the in- 

 crease in the missile's distance 

 from C does not affect the mo- 

 mentary description of areas, which 

 depends only on the rate of motion 

 perpendicular to the radius vector). 

 This equality continues through- 

 out the motion, since neither the 

 missile nor the point a changes 

 its rate of describing areas around 

 C Consequently, when the mis- 

 sile reaches b, at which time the 

 point a has come to c, the total 

 areas described are equal, that is, 

 area aCbA. = sector aCc, or, re- 

 moving common sector aGb 



area aAh == sector bGc, 

 that is, since aA.h is appreciably a 

 parabola and «M6 a straight line 

 perpendicular to the axis AM, 



•2 1 



ah . AM = ^ ic . ahC 



'. ; or, putting AM=7i, iC=r, 



westerly deviation=6c= 



4 h 



ah. 



Compared with ah, be is so small that we may put ac for ah 

 without appreciably affecting the result ; and obviously, if 

 2< is the time of flight (t for the ascent or descent), P the 

 earth's rotation period, we have 



ac= — 2-r 

 P 

 1. r I 2t -, /ih\ l^Trht 



wherefore 6c= — 2jr| — 1 = 



P \3/ 3P 



Cor. — If the place of projection is in latitude ,\, the 

 westerly deviation is 



16s-/t< cos X 

 3R 

 Sotc. — I said incorrectly that Mr. Bray's result at 

 p. 393, letter 853, was correct. It is only half the actual 



