84 



Mr. F. Galton on Verifying 



[Mar. 15, 



the transmission Onwards both of the contents of the bowel and of the 

 resulting stimulation. The contraction of these longitudinal fibres would 

 also mask the details of the process to external observation. The inter- 

 mitting contractions of the sphincter under a continuous stimulation 

 may represent the successive waves of peristaltic action when the intes- 

 tinal contents are abundant. It is further to be noted that the presence 

 of the instrument in the anus, after the effect of its introduction had 

 passed off, was the source of no stimulation, just as contents may be at 

 rest within the bowel, and if they are not moved, and do not irritate the 

 mucous membrane, may excite no peristaltic action. 



EXPLANATION OF TEACINGS. 



Fig. 1. Effect on contraction of sphincter of the injection into the rectum of a small 

 quantity of air at *. a, fall in pressure due to the inhibition of the contrac- 

 tion ; b, rise due to the slowly returning contraction. 



Fig. 2. Effect of the introduction of the instrument, a, sudden rise of lever at moment 

 of introduction, due to the exposure of the instrument to the pressure of the 

 sphincter (the top of this line represents the degree of previous contraction) ; 

 b, initial rise due to increased contraction ; c, fall from partial inhibition ; 

 d, subsequent contraction, rising to a greater degree than the initial contrac- 

 tion, and subsequently falling slightly. 



Fig. 3. Effect of cough, a, pressure of tonic contraction of sphincter (the slight irre- 

 gularities are due to pulse-waves) ; b, fall in pressure, due to the movement 

 of the' instrument by the cough ; c, initial contraction ; d, relaxation of inhi- 

 bited sphincter ; e, e, e, rhythmical variations in subsequent rise. 



Figs. 4, 5, 6. Rhythmical variation in contraction of sphincter under the influence of a 

 continuous injection of air into the rectum, a, a, a, waves of secondary 

 rhythm. 



Figs. 1, 2, 3, 4, & 6 are from the case of injury to the sacral nerves. Fig. 5 is from a 



case of disease of the dorsal region of the spinal cord. 

 The vertical lines represent seconds of time. 



V. " Description of the Process of Verifying Thermometers at 

 the Kew Observatory." By Francis Galton, F.R.S. Re- 

 ceived March 1, 1877. 



It may be of interest to describe the method recently adopted at the 

 Kew Observatory of verifying thermometers by comparison at different 

 temperatures with a standard instrument, since a large proportion of the 

 various thermometrical determinations made by English physicists are 

 dependent for their accuracy upon that of the verifications at Kew. 

 Many thousands of thermometers have already been verified by the 

 apparatus about to be described. 



Up to the year 1875 the apparatus for this purpose at the Kew 

 Observatory was of the rudest character. 



It was simply a glass jar 9| inches wide and 18 inches deep, filled 



