18 



KNOWLEDGE ♦ 



[Jan. 



18fc5 



Before closing this letter, may I be allowed to ask for informa- 

 tion, by the editor or other expert in the higher optics, as to tlio 

 present most satisfactory explanation of erect vision, spite of the 

 inversion of object -images on the retina P In a very able article 

 of Blaclncood's Mainninc, so long since as June, 1812, of the Berk- 

 leyan theory of vision and idealism, the reviewer is puzzled by the 

 same anomaly. lie therein invites Sir IJavid Brewster to solve 

 this crux, a solution for which we are still waiting. I c.armot think 

 Kepler's nitioncle, in his " Supplement to Vitellio," at all satis- 

 factory. Robert Lewi.xs, M.D. 



Army and Xavy Club, Dee. 20, ISSt. 



[I rather fail to see in what Dr. Lewins's theory differs from 

 that of Herren Fichte, Hegel, & Co. In connection with the para- 

 graph with which the letter above concludes, see p. IfiS of the 

 current volume of Knowledge. — Ed.] 



THE EFFECT OF TEA— TUE DUALITY OF THE BEAIN. 



[1553] — I had abstained from taking tea or coffee for nearly a 

 year, but, by w;iy of experiment, 1 took a cup of tea a few days 

 ago at about half-past eight in the evening, the result being that I 

 was in.able to get to sleep until about live the next morning. 



On the following day I tried the experiment again, taking the 

 tea about tix instead of half-past eight. The result was exactly 

 same. 



If tea is not injuritjus, sleepless nights are. 



On the other hand, ] am acquainted with a lady and gentleman 

 who assert that tiiey use tea as a remedy for sleeplessness. 



If unable to sleep, they rise and make tea, and it never fails to 

 jiroduce the desired result. 



If constitutions differ thus. 



How can we all agree ? 

 'Tis useless, then, to make a fuss 



On coffee, wine, or tea. 



An interesting point with regard to the duality of the brain 

 is the fact that, when one leaves a place, one is often conscious of 

 having forgotien something. 



How common is the expression, " I'm sure I had something else 

 to do." 



And frequently the journey is over before the other half of the 

 brain enables us to remember ii'hut that " something" is. 



C. CAKV.-i-WlLSON. 



IS TEA IXJUraOUS?— VEGETABLES ;■. MEAT. 



[1E54J — Having made many experiments on mj'self, I am 

 able to say from experience that it is. After giving up 

 tea for a time, I find that when I return to it that its 

 taste is at first unpleasant, and were it not for the sugar 

 and cream wonld be undrinkable. Soon after taking, it acts 

 as an excitant, making me feel very clear mentally, and lit for 

 studious work, and I can work well whilst the excitability lasts. 

 Then follows a feeling of depression, which lasts for a variable 

 time ; during this periotl I am unfit for all work and in a low mood, 

 which nothing but time and exercise will remove. If the tea be 

 taken in the afternoon — say, after 5 p.m. — there is no sleep for me 

 until 2 am. next mom. These effect^-, I must say, seem to wear 

 away as the habit becomes usual. My first experiment, some six 

 years ago, showed that tea is a strong paralysant of the nerve- 

 centres governing the lower extremities. I hati given up tea for a 

 month ; then at the house of an Anglo-Indian, I had some strong 

 Indian tea at G p m., and a cup of black coffee at 10 p.m. I went 

 home at midnight, and found I wa.s intoxicated and had not proper 

 control over my loner limbs. I retired to bed, but did not sleep 

 until 1 a.m. ; I simply laid on my back, thought of nothing, but 

 hummed one refrain over and over again. How I was next day I 

 do not recollect. This and like trials showed me that tea is bad, 

 and I only use it now when out visiting. Let other readers of 

 KxoHLEDGE try the same experiment, and I promise them like 

 results. 



L. 0'.Shea Dillon, with many others, labour under a wrong idea 

 when they think that vegetarians (so-called) are vegetable-arians. 

 My food, as a non-flesh eater, contains very little greenstuff; peas, 

 be.'jns, lentils, rice, barley and oaten grits are my staple foods, to 

 which I add a little carrot, turnip, and onion. These latter I use 

 for bulk, flavour, and to supply a little vegetable acid. But these 

 grains, with farinaceous puddings and fruit of every kind, fresh 

 and dried, are my chief foods. Cabbage, greens, &c., I do not 

 much use, nor even the potato above once or twice a week, as I can 



get my nourishment cheaper and less bulky from the cereals an«3 

 pulses. T. K.'Alunson, L.U.C.P. 



[There can be no doubt that the flesh-eati'ig races have been the 

 conquerors of the world. It suffices to contrast the pusillanimous 

 vegetarian Hindu with the brave and soldierlike meat-eating Sibb, 

 to seetowliat phytophagism reduces a jieople. We could never have 

 held India for a year, but for the condition to which its predomi- 

 nant races have been reduced by their vegetable die,.. — En.] 



LETTERS RECEIVED AXD SHORT ANSWERS. 



CiEoRGE Lacy. I suspect that the reply to your letter has been 

 delayed through great pressure of business. You are, however, 

 entirely in error as to any connection subsisting between the adver- 

 tiser and the Editor or ])roprietor3 of K.NOWI.KDGE. I know nothing 

 of the gentleman to whom you wrote, and have never had the 

 slightest communication, oral or in writing, with him in my life. — 

 G. G. HAED1NG11A.M. Can you give me the approximate date at 

 which you sent the book ? because it has certainly never reached 

 me. Mighty as Newton was as a mathematician and man of 

 science, he was assuredly no authority on any theological question. 

 You know, of course, that ho suffered under mental aberration iii 

 the years lb92 and IGDa ; and it was during this period of temporary 

 insanity that, at Dr. Bentley's request, he wrote his four letters 

 on the existence of the Deity. So, too, his " Observations oa 

 the rrojjheciea of Daniel and the Apocalypse of St. John" 

 hardly read like the composition of a man in full possession o5 

 his intellectual faculties. Your hint about the suggested alteration 

 in our way of measuring time shall receive consideration. — 

 FACiEfi.^T. Thanks; the two typographical errata to which you 

 invite attention arc corrected ehewherc. Augite occurs as a trap 

 or intrusive material in metamorphic or any other rock. In the case 

 referred to it must have belonged to the volcanic tufa. You are 

 right in your interpretation of the letters. You can easily construct 

 the diagram for yourself. Describe a circle of one inch in diameter. 

 Call this the earth. Then, with the same centre, describe another 

 circle round this of two inches in diameter to stand for the moon's 

 orbit. Draw any diameter of the earth, and at the extreniity of it 

 draw a tangent to the one-inch circle (of course, at right angles to 

 the diameter). This will obviously cut the outer circle at two points. 

 Then will this tangent represent the horizon of the spectator, and 

 the two places where it cuts the two-inch circle, the distance of 

 the moon from the observer at the time of her rising and setting. 

 While the place where the diameter produced cuts the semicircle 

 shows how far she is from us when overhead. A glance at such a figure 

 without any measurement will suffice. Sir Edmund Beckett's ex- 

 planation rather supplements than contradicts mine. I heartily re- 

 ciprocate your kind wishes. — I!. L. Tidmax. Fit only for the unfortu- 

 nate creatures whose fatuous folly prompts them to believe in so 

 gross an imposture as slate-writing, or (Heaven save the mark ! ) 

 " psychography." As for that most respectable and ingenuous 

 person, Madame Blavatzky, see the Madras Christian CoUcije Matja- 

 zive for November. — A. Le Suer. Thanks for your very useful 

 hint. — Ktima. The meridian of 180° may correspond to either one 

 of two days, for a perfectly obvious reason. See reply to " Istoria," 

 in p. 51.3 of the volume just concluded. — JLD. Note that I spoke 

 of sensations, not of either emotion or volition. But the two last 

 states of consciousness may obviously co-exist, because I may will 

 to knock a man down with whom I am (absolutely simultaneously) 

 angry for a gross insult. Under ordinary circumstances, though, 

 what I may not very scientifically descri'oe as different sorts of 

 consciousness, must be separated from each other by some interval, 

 be it ever so minute. I heartily reciprocate your good wishes. 

 — G.A. M. Too great a heap of matter just now to leave room 

 for reports of lectures. — C. N. You will see from letter 1552, 

 page 17, that Dr. Lewins has already had his own say upon 

 what he claims as his theory, but which is really only a re-state- 

 ment in other words of ideas developed by Berkelej' in this 

 country, and later on by some of the German metaphysicians. — 

 Undek Grad. (L.U.). Your intimation that you "shall have no 

 hesitation in risking, say, a matter of £5 as to the lionu.-Jides oS 

 your contention" is a stupendous puzzle to me. Do you think 

 that the Messrs. Wymans or I am prepared to risk a prosecution 

 under 16 and 17 Vict., c. 110, s. 3, by turning 74, Great Queen- 

 street into a tetting-house ? Heat is nothing but another /oi-Jii of 

 motion. If yon check the rotation of a fly-wheel by a brake or 

 clutch you set up molecular vibration or motion in that brake 

 which constitutes, and becomes apparent as, heat, and, pro tantOy 

 diminishes the motion of the fly-wheel. I am not concerned to 

 defend all that has been written about the retardation of the rate 

 of the earth's axial rotation, for the simple reason that, in the 

 existing condition of our knowledge, no jiroo/ whatever exists of 

 such retardation. Its assumption serves to explain certain other 

 phenomena; but that is a very different thing indeed. 



