VOL. XVIII.] PHILOSOPHICAL TRANSACTIONS. ' 621 



during that time. But if you desire greater accuracy add 3.10, its 200tli part, 

 and you will have 6'24.30 for the true height, and 41 .62 for the mean height by 

 those 15 years observations; and 414.1 for the mean quantity of half pounds. 

 My way of gauging by weight is grounded on 22.7368 cubical inches of rain- 

 water being equal in weight to one pound, or 12 ounces Troy; so that dividing 

 any superficies in inches, of a vessel for receiving the rain-water, by the before- 

 mentioned number, it will give the pounds and parts that will raise the water 

 on that superficies, with upright sides, just an inch; and thus I found that 

 4 974 pounds would fill a cylinder equal at the bottom to my tunnel, and 1 

 inch high, which is nearly 5 pounds, and which will only raise the cylinder 

 higher by -r^o-th part. 



P.S. It is remarkable the great harmony there is between the mercurial 

 standards at London and here at Townley ; for by a whole month's observa- 

 tions, Mr. Flamsteed was pleased to send me, the mercury always rose and fell 

 both there and here exactly at the same time. I always found it rather more 

 than -^ of an inch lower here than at London, because though we are seated in 

 a seeming valley, in respect of the neighbouring grounds, yet we are consider- 

 ably higher than the other low lands near the sea, where the standard differs 

 little from that at London. I suppose you may not be displeased with two 

 remarkable observations, made both by Mr. Flamsteed and me at the same time, 

 viz. Nov. 18, 1674, when finding the mercury to descend both very fast and 

 very low, we watched it very nicely, and both of us observed that at 2 in the 

 afternoon it was rather falling, and rather rising at 4, at which times the height 

 was here only 27.63 inches, and at London -r'oths higher. 



ji Case of Lumbago Rheumatica Convuhiva. By Robert Pitt, M. D. F. R. S. 

 Extracted from the Latin. N° 208, p. 58. 



A man aged 35, after taking cold was seized with feverish symptoms, which 

 terminated in a most violent pain in the loins and hip. The pain was so acute 

 as to throw him into profuse sweats, which ran down in drops from his hair 

 and face. He could neither lie down on a bed, nor stand upright, nor sit in a 

 chair, but to assuage his pain had recourse to pressing his belly against the bed- 

 stead. Yet he could not long remain even in this posture ; but, being seized 

 with convulsions, would fall down on the floor if not prevented by those who 

 were present. After the first convulsive seizure he would remain motionless, 

 and in regard to his limbs as helpless as an infant. His arms and legs would 

 become inflexible, and the mouth so closed, that it would be scarcely possible 

 to get a spoon into it. These convulsions returned by paroxysms, but not 



