354 



Mr. J. N. Lockyer on Spectroscopic [May 19, 



tions have been made, several of which are recorded on the Table, and in 

 health no cases have been found which depart from the curve more than 

 those indicated on it. 



The observations made on the author are represented by simple black 

 dots, those made on others are encircled by a ring ; great size of a dot 

 indicates that more than one independent observation has produced exactly 

 similar results. 



In none of the cases have measurements been made after violent exer- 

 cise. Differences in the height and age of the subjects experimented on 

 have not been found to produce any appreciable effect. 



The trace from infants has not been examined. 



From the equation 0:1/ = V ' x . 1c the length of the second part of the 



pulse trace may be represented in terms of a?, as ^ ^ — ; and as from 



the nature of y it cannot be less than unity (no pulse having been seen with 

 two contractions or more between two successive closures of the aortic 

 valve), the limit of cardiac rapidity may be deduced to be 322 in a minute 

 (£=47) ; but it is scarcely probable that pulses of such a rate could remain 

 so sufficiently long to be counted. 



In many cases of disease implicating the circulatory system, the equa- 

 tion given above indicates that the duration of the first part of the heart's 

 action is not normal ; thus, in a boy suffering from typhoid fever, on the 

 second day after the pyrexia had ceased, and when the temperature was 

 below the normal, xy was found =225 '25, where £=60, which differs 

 from the equation 



^67x47 = 190-82, 

 which shows that the length of the first part is considerably too short in 

 the former. In the same case, three days later, the patient rapidly im- 

 proving, with x = 56' 5, 

 ccy = 188, 



which is much nearer the calculated normal result, 180'5, than on the 

 former occasion, the trace keeping pace with the other physical changes. 



It is probable that many other imperfections in the circulatory system 

 can be similarly indicated, and it has been shown above with what facility 

 a diagnosis may be arrived at. 



VI. " Spectroscopic Observations of the Sim/' — No. VI. 

 By J. Norman Lockyer. Received April 27, 1870. 



The weather lately has been fine enough and the sun high enough 

 during my available observation-time to enable me to resume work. 



The crop of new facts is not very large, not so large as it would have 

 been had I been working with a strip of the sun, say fifty miles or a hun- 

 dred miles wide, instead of one considerably over a thousand — indeed, nearer 

 two thousand in width ; but in addition to the new facts obtained, I have 



