VOL. I.] PHILOSOPHICAL TRANSACTIONS. 67 



broader than the other ; and let them both be put into a ring of brass, and so 

 fastened with cement, that their plane surfaces may be exactly parallel, and the 

 convex side of the plano-convex glass lie inward, so as not to touch the flat of 

 the other. Then fill the space between, by a small hole in the side of the brass 

 ring, with water, or oil of turpentine, or spirit of wine, or saline liquors, &c, 

 after which stoj) the hole with a screw. Then, according to the different re- 

 fraction of the liquors, shall the focus be longer or shorter. 



This is but one instance, among many, of the possibility of making a glass, 

 ground in a smaller sphere, to constitute a telescope of a much greater length. 

 Though I must add, that of spherical optic glasses, those are the best which are 

 made of the greatest sphere, and whose substance has the greatest refraction. 



Shining JForms in Oysters, By M. AuzouT. N" 12, p. 203. 



These observations occur in the French journal of April 12, l666, in two 

 letters, written by M. Auzout to M. de la Voye ; the substance of which may 

 be reduced to the following particulars : 



M. Auzout causing more than 20 dozen of oysters to be opened by candle 

 light, saw on removing the light shining worms in them of three sorts. One 

 sort was whitish, having 24 or 25 feet on each side, forked ; a black speck on 

 one side of the head (taken by him for a chrystallin), and the back like an eel, 

 stripped of her skin. The second red, and resembling the common glow worm, 

 with folds on their backs, and feet like the former ; and with a nose like that 

 of a dog, and one eye in the head. The third sort was speckled, having a head 

 like that of a sole, with many tufts of whitish hair on the sides of it. 



Among them he saw two more firm than the rest, which shone all over; 

 and when they fell from the oyster, twinkled like a great star, shining strongly, 

 and emitting rays of a violet-light by turns, for the space of 20 seconds. Which 

 scintillation the observer imputes to this, that those worms being alive, and 

 sometimes raising their head, sometimes their tail, like a carp, the light in- 

 creased and lessened accordingly; seeing that when they ceased to shine, by 

 bringing back the light, he found them dead. 



Some Observations on the [medical] Effects of Touch and Friction, 

 By Mr. Oldenburg. N' 12, p. 207- 



Touch and friction (the author observes) have been considered by some as 

 no inefficacious agents in the cure of many diseases and infirmities. 



1 . The illustrious Lord Verulam, in his History of Life and Death (Hist. 6. 

 ^ 3.) observes, that the motion and warmth excited by friction draw forth 



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