350 



THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



to it (I will copy the words written down at the 

 time) " a most strongly - marked interrogatory 

 Bound at the end." He also gave to "Ah," which 

 he chiefly used at first when recognizing any per- 

 son or his own image in a mirror, an exclamatory 

 sound, such as we employ when surprised. I re- 

 mark in my notes that the use of these intona- 

 tions seemed to have arisen instinctively, and I 

 regret that more observations were not made on 

 this subject. I record, however, in my notes that 

 at a rather later period, when between eighteen 

 and twenty-one months old, he modulated his 

 voice in refusing peremptorily to do anything by 

 a defiant whine, so as to express " That I won't ; " 

 and again his humph of assent expressed " Yes, 

 to be sure." M. Taine also insists strongly on 

 the highly-expressive tones of the sounds made 

 by his infant before she had learned to speak. 

 The interrogatory sound which my child gave to 

 the word mum when asking for food is especially 

 curious ; for if any one will use a single word or 

 a short sentence in this manner, he will find that 

 the musical pitch of his voice rises considerably 

 at the close. I did not then see that this fact 

 bears on the view which I have elsewhere main- 

 tained, that before man used articulate language, 

 he uttered notes in a true musical scale, as does 

 the anthropoid ape Hylobates. 



Finally, the wants of an infant are at first 

 made intelligible by instinctive cries, which after 

 a time are modified in part unconsciously, and in 

 part, as I believe, voluntarily as a means of com- 



munication — by the unconscious expression of 

 the features — by gestures and in a marked man- 

 ner by different intonations — lastly by words of 

 a general nature invented by himself, then of a 

 more precise nature imitated from those which 

 he hears ; and these latter are acquired at a won- 

 derfully quick rate. An infant understands to a 

 certain extent, and as I believe at a very early 

 period, the meaning or feelings of those who tend 

 him, by the expression of their features. Thefe 

 can hardly be a doubt about this with respect to 

 smiling; and it seemed to me that the infant 

 whose biography I have here given understood a 

 compassionate expression at a little over five 

 months old. When six months and eleven days 

 old he certainly showed sympathy with his nurse 

 on her pretending to cry. When pleased after 

 performing some new accomplishment, being then 

 almost a year old, he evidently studied the expres- 

 sion of those around him. It was probably due 

 to differences of expression, and not merely of 

 the form of the features, that certain faces clearly 

 pleased him much more than others, even at so 

 early an age as a little over six months. Before 

 he was a year old, he understood intonations and 

 gestui'es, as well as several words and short sen- 

 tences. He understood one word, namely, his 

 nurse's name, exactly five months before he in- 

 vented his first word mum ; and this is what 

 might have been expected, as we know that the 

 lower animals easily learn to understand spoken 

 words. — Mind. 



ON THE PROBABLE ORIGIN" AND AGE OF THE SUN. 



Et JAMES CEOLL, LL. D., F. E. S.» 



THE total annual amount of radiation from the 

 whole surface of the sun is 8,340 x 10 30 foot- 

 pounds. To maintain the present rate of radia- 

 tion it would require the combustion of about 

 1,500 pounds of coal per hour on every square 

 foot of the sun's surface ; and were the sun com- 

 posed of that material it would all be consumed 

 in less than 5,000 years. The opinion that the 

 sun's heat is maintained by combustion cannot 

 be entertained for a single moment. Mr. Lock- 

 yer has suggested that the elements of the sun 

 are, owing to its excessive temperature, in a 

 state of dissociation, and some have supposed 



1 Of H. M. Geological Survey of Scotland, and author 

 of " Climate and Time." 



that this fact might help to explain the duration 

 of the sun's heat. But it must be obvious that, 

 even supposing we were to make the most ex- 

 travagant estimate of the chemical affinities of 

 these elements, the amount of heat derived from 

 their combination could at most give us only a 

 few thousand years' additional heat. Under 

 every conceivable supposition the combustion 

 theory must be abandoned. 



It is now generally held by physicists that 

 the enormous store of heat possessed by the sun 

 could only have been derived from gravitation. 

 For example, a pound of coal falling into the 

 sun from an infinite distance would produce by 

 its concussion more than 6,000 times the amount 



