6i8 



NATURE 



[April 2?>, 1 88 1 



its wishes and inducing the nu'se to comply with them cannot 

 be definitely looked at as a case of self-con=ciou5ne s, but only 

 of consciousness. This is one of the most intricate questions to 

 decide — 7uhe>i the child distinguishes its oAvn body, head, 

 hands, &c., from other objects, as belonging to himself. The 

 first time a child says " I" and "me," in the correct sense, it 

 may be considered to have passed the limit. The formation of 

 ideas by associating impressions, as well as the formation of 

 general ideas (Begriffc) by unitmg similar qualities of different 

 objects, is intellectual work done by the child long before it 

 knows anything of its own individuality. It seems to me that 

 self-consciousness does not arise suddenly, but by degrees, after 

 many experiments have shown the difference between touching; 

 his own body and external objects with his little hand. 



I have been occupied with psychogenetical problems since 

 nearly four years, continually collecting facts. Should you be 

 able to awaken some interest for thee most important investii;a- 

 tions (I mean the physiology and psychology of infants), I think 

 the trouble taken would soon be repaid by the results. 

 I am, sincerely, 



Dr. Wm. Preyer, Professor 



P.S. — Perhaps the observations and experiments on the senses 

 (sight, hearing, smell, taste) of new-bom animals and infants 

 which I published in /Cosmos (Zeitschrift herau^gegeben von E. 

 Krause), vol. iii. pp. 22-37, 12S-132 (1S7S, Leipzig), may have 

 some little interest. In England Romanes has written very able 

 papers on the development of instinct and intelligence. His 

 address is 18, Cornwall Terrace, Regent's Park, London. 



Yours, &c., W. P. 



ABNORMAL BAROMETRIC GRADIENT BE- 

 TWEEN LONDON AND ST. PETERSBURG 

 IN THE SUN-SPOT CYCLE 



"DEFORE alluding to the subject which forms the heading of 

 the present communication, I must apologise for having 

 allowed some rather serious errors to creep into the figures given 

 for the barometric abnormals of London in my letter to Nature, 

 vol. xxiii. p. 243. The errors were cansed by a friendly com- 

 puter taking the differences from the mean for each year incor- 

 rectly in one or two cases. 



I am glad to say however with respect to the relation betw een 

 the barometric abnormals as there given and the sun-spot 

 numbers, that far from its being vitiated by the corrections 

 which have now been made, they on the contrary considerably 

 strengthen it, as is evident when the following corrected values 

 for the mean cycles are compared with those given in my former 

 letter :— 



London 

 Annual Baromct)-ic Abnormals, Mean Cycles 



Tf now we take these corrected figure.s, and subtract from them 

 tho^e giveir in Nature, vol. xx. p. 28, for St. Petersburg 

 (reduced to inches), which comprise very nearly the same period, 

 we get for the abnormal annual baric gradient from London to 

 St. Petersburg in each year of the mean cycle, the follo\\ing 

 figures : — 



Abnormal Annual Barometric Gradient bctwccnlLondon and St. 

 Petersburg 

 (B) (A) 



Maximum years m fifth line. Minimum years in seventh line. 



^ ^ 



r CQ g >" 



< I 



baric gradient oscillation of single period, closely following 

 inverse sun-spot oscillation. 



