22 



tive velocity is below Prof. Erman's minimum limit. Thus, in the 

 instance of the meteors of August 10th, the average discrepancy of 

 any single meteor's relative direction, from the common convergent 

 point, is, according to Prof. Erman, more than 10°, and must have a 

 maximum of not less than 25°. The Professor remarks, that this dis- 

 crepancy may arise 



1. From difference of their elliptic orbit round the sun. 



2. From their mutual action. 



3. From the earth's attraction. 



The first and second causes, on Prof. Erman's hypothesis of an 

 elliptic ring, could not produce a discrepancy of more than 2° or 3°. 

 In order that one of 10° should result from the third cause, it would 

 be necessary that the relative velocity should be less than one third 

 of that of the earth, in which case the orbits of the meteors would be 

 inclined less than 14°, to the ecliptic. The author concludes, that a 

 ring so near the earth, must be subject to very great perturbations, 

 and if there is one, he thinks that no observations which we can make 

 will enable us to calculate its motions with any degree of accuracy. 



Dr. Ludlow and Dr. Mitchell presented a report from the 

 committee, to whom had been referred Professor Tucker's 

 paper, entitled " Psychological Observations on the Siamese 

 twins, Cheng and Eng, made in 1836." 



Soon after the arrival of the Siamese twins into the United States, 

 now above eleven years ago, it appeared to me, says Prof. Tucker, 

 that they afforded an opportunity of making some psychological ob- 

 servations which had never before been presented, unless perchance 

 by some like freak of nature. 



Here were two individuals who were precisely similar in all the 

 circumstances likely to influence either their bodies or minds. They 

 had always breathed the same air, eaten of the same food at the 

 same time, slept and waked together, and taken the same exercises 

 both in kind and quantity, and at the same moment. Whatever had 

 affected the senses of the one, had affected those of the other. Their 

 sources of knowledge, whether from observation or reasoning, and 

 their lessons both of experience and education, were precisely the 

 same. They had also been sick and well together, and may be sup- 

 posed to have had in all respects, the same pleasures and pains, bodily 

 and mental. 



Placed in circumstances so similar, or rather identical, these twins 

 suggested the inquiry whether there was a correspondent resemblance 



