April 20, 1883.] 



SCIENCE. 



303 



As it turns, the radiating bars on it are brouglit 

 to a vertical position one after the other ; and, 

 while passing this position, thej- raise the lever 

 suspended above, and, by the action of the piu 

 at its end, keep the circuit open. They are so 

 placed and gauged that thej- hold the nircuit 

 open from 55 to GO seconds of the first, and 

 then of the second minute. 



Each break in the primary circuit causes a 

 distinctly audible sound in the ear-telephone. 

 This sound is so loud that I have sometimes 

 heard it across the room. As the circuit is 

 broken each second for the first fifty-five sec- 

 onds of each full minute, and for the full thirtj' 

 of the last half-minute, the time-transmitter 

 gives a series of seconds signals easily received 

 at any telephone in connection with it. The 

 intermission of five seconds at the end of each 

 full minute serves to notify- the receiver that 

 the next minute is about to begin, and thus 

 saves him the trouble of counting. 



In using the time-transmitter, the person who 

 desires the time calls me up bj- telephone, and 

 I start the transmitter at the beginning of some 

 minute by his time. The correspondents are 

 usually jewellers, and do not need to be told 

 the minute at which the transmitter began. If 

 they do need the minute, it can be given them 

 verballj' hy the Blake transmitter. The suc- 



cession of beats and intermissions gives the 

 receiver four opportunities for comparison ; 

 viz., the beginning of the first, second, and 

 third minute, and the end of two minutes and a 

 half. 



An important feature of this method is its 

 capacity' for transmitting time to several or man j' 

 persons simultaneousl}'. In order to test this. 

 Manager Keech of this place obliginglj' called 

 up all the exchanges connected with us. Some 

 did not respond ; but those who did — a dozen 

 or fifteen in number, and distant in all directions 

 from ten to seventy-five miles from us — all 

 iieard the beats of the transmitter distinctly, 

 except at Port Huron. From this and some 

 other tests, I concluded, that, by this method, 

 the time could be received by at least twenty- 

 five telephones simultaneously. 



M. W. Harrington. 



PARENTAL INSTINCT AS A FACTOR 

 IN THE EVOLUTION OF SPECIES. 



In a recent lecture at the Sheffield scientific 

 school. New Haven, the writer called attention 

 to the lack of maternal care as one of the 

 probable causes, though usually overlooked, 

 of the extinction of many of the large and 

 powerful reptiles of the mesozoic age, and of 

 the large mammals of the tertiarj'. The veiy 

 small size of the brain and its low organization, 

 in these earlj' animals, are now well known, 

 and we are justified in believing that their in- 

 telligence or sagacitj- was correspondingly 

 low. The.y were doubtless stupid and sluggish 

 in their habits, but probablj' had great powers 

 of active and passive resistance against corre- 

 spondingly stupid carnivorous species. But, 

 unless the helpless young were protected by 

 their parents, thej' would quickly have been 

 destroyed ; and such species might, in this way, 

 have been rapidly exterminated whenever they 

 came in contact with new forms of carnivo- 

 rous animals, having the instinct to destroy the 

 new-born j'oung of mammals, and the eggs 

 and young of oviparous reptiles. 



Thus it would have come about, that the 

 more intelligent forms, bj' the development of 

 the parental instinct for the active protection 

 of their .young against their enemies, would 

 have survived longest, and therefore would have 

 transmitted this instinct, with other corre- 

 lated cerebral developments, to their descend- 

 ants. This mode of natural selection must 

 alwa3-s have been a very active one, wherever 

 carnivorous mammals, birds, and reptiles, have 

 existed in contact with herbivorous species. 



