324 



with the fingers, the latter becomes tightly applied to the extremity of 

 the exhauster, and the air is sucked out from the ball by the mouth. 

 When it is considered that nearly all the air has been subtracted, the 

 stopcock is turned before taking the exhauster from the mouth, and 

 while the suction is yet going on ; a little careful manipulation is now 

 required to remove the ball from the exhauster without allowing the 

 air to re-enter. When the operator has succeeded thus far in the manu- 

 facture of his ball, the next step is to make it as round as possible. 

 This is effected by two " rounders" (Figs. 6 and 7), which I have 

 sketched; these consist of polished metal; 

 they are hollowed out slightly from centre Figs. 6 and 7. 



to surface ; one of them is furnished with a 

 handle, and the other is to be laid on the 

 table when using them. They are first heated 

 by pouring some warm oil on the polished 

 hollowed surface ; the index ball is put on 

 the one which is stationary, and the other 

 " rounder" is gently worked over it in a cir- 

 cular manner until the ball has become per- 

 fectly round ; the rounders are heated at in- 

 tervals by adding more hot oil to their polished surfaces. I need not 

 mention the necessity there is for iron moulds of different bulk, in order 

 to produce balls of different sizes, adapted to the variously sized tubes. 



I have now completed the description of my Hsemodromometer. 

 That I do not expect it to be considered as anything like a perfect in- 

 strument, I have already said. I know that some physiologists will 

 object to it on account of the complexity of previous operations which 

 must be performed when working with it ; but will any one, I ask, 

 give the preference to Volkman's instrument simply because of the 

 trouble of working which mine would cost the operator ? If so — if it 

 is desirable that instruments be made with a view rather to save the 

 operator work, than to attain to accuracy of result — then have I laboured 

 in vain. 



The following donations were presented: — 



1. From the Society of Antiquaries of London the following publica- 



tions of the Society : — 



"Layamon's Brut," edited by Sir F. Madden. 3 vols. 



" Eotuli Scaccarii Normannise," edited by T. Stapleton. 2 vols. 



" Codex Exoniensis," edited by B. Thorpe. 1 vol. 



2. From Joseph Gurney Barclay, Esq., " Astronomical Observations, 



1862-64." 



3. From the Commendatore Negri Cristoforo, "La Storia Antica Eesti- 



tuita." 



The thanks of the Academy were voted to the donors. 



