482 PHILOSOPHICAL TRANSACTIONS. [aNNO I76O. 



here. We may believe that the quicksilver used by Mr. de la Croyere was im- 

 pure, and therefore might sooner become an amalgama than mercury. Though 

 in the experiment made by Mr. Lomonossow the quicksilver fell to 1 26o°, yet 

 this philosopher says, that he could not sufficiently observe in his hurry whether 

 the ball might not have received some crack, and the quicksilver thereby perhaps 

 might have had liberty to fall the lower, which otherwise would not have hap- 

 pened; for the same thing happened to Mess. Braun, Zeicher, and ^pinus, 

 that the balls of their thermometers were cracked and broken. 



In making these experiments, it is to be observed, that it is necessary to use 

 fuming spirit of nitre, or of such as is evaporated till the fumes become red ; for 

 the common aquafortis which is used had not the desired effect. Mr. ^pinus 

 has found that this experiment is very easily and speedily made in the following 

 manner. Take spirit of nitre, cooled as much as possible, and with it half fill a 

 wine-glass, throwing in as much snow at the same time, and stirring it till it 

 becomes of the consistence of pap : then you have almost in an instant the ne- 

 cessary degree for the congelation of the quicksilver. Now in reflecting on the 

 procedure of other philosophers, especially of Mess. Muschenbroek and Reau- 

 mur, for producing artificial cold by the commixtion of snow with aquafortis, as 

 the former has mentioned in his edition of the Experiments of the Academy of 

 Florence, tom. i. p. 1/4, and Mr. Reaumur, in the Memoirs of the Academy of 

 Sciences of Paris for the year 1/34, it is astonishing how it happens that these 

 learned men have not obtained, by a great deal, the degree of cold produced by 

 the gentlemen of the academy of Petersburgh ; for their manner of making the 

 experiments does not seem to differ much from that of Mr. Braun, as to what 

 relates to any essential circumstances, nor from the manner mentioned before, 

 so as to hinder them from producing effects nearly equal. Indeed a certain de- 

 gree of external cold appears absolutely necessary to the experiment. Mr. Spi- 

 nas, who made it the 28th of December, in a room where De Lisle's thermo- 

 meter showed 1 22 degrees of cold, cooled the spirit of nitre in liquifying snow to 

 150 degrees, and the snow which they used came to the same degree; in making 

 the mixture, the result was an augmentation of cold to 300 degrees. It must 

 then happen, that they had obtained the surprizing degree necessary to congeal 

 the mercury; which Mr. Zeicher also at length obtained; the degree of cold of 

 the air being the 1 7 5th degree of De Lisle's thermometer, or the 30th of that 

 of Fahrenheit. 



LXV. Of a Complete Luxation of the Thigh Bone, in an Adult Persony by Ex- 

 ternal Fiolence. By Mr. Charles fVhilt, Surgeon at Manchester, p. 676. 

 As Robert Hogg, (a farmer in Clyfton, about 4 miles from Manchester) a 



strong, robust middle-aged man, was taking a load of wheat from off a horse 



