481 PHILOSOPHICAL TRANSACTIONS. [aNNO 173]. 



nary vein, 6 inches long, with their several ramifications, freed from the tra- 

 chea and substance of the lungs, as if very accurately dissected. This case he 

 observes is very extraordinary, and not to be paralleled in the writings of phy- 

 sical authors. 



A small acquaintance with the structure of the lungs sufficiently evinces the 

 impossibility of the fact, as there stated. Therefore, not doubting the veracity 

 of the author. Dr. N. always believed him to be deceived by a polypus of the 

 vein, which might be coughed up in the manner described. 



But the following case will put this matter in another light. July 18, 1730, 

 Dr. N. was consulted on behalf of a person, living in Essex, who was asthmatic, 

 and coughed up phlegm resembling worms: to remedy which, he directed the 

 use of a lac ainmoniacum with squills; by means of which he expectorated 

 more easily, but continued still to cough up the same substances. 



July 11, 1731, on the road to London, the patient was seized with a shiver- 

 ing, and pleuritic pains; his tongue was white, pulse hard and quick, &c. By 

 repeated bleeding his pains decreased, but the cough remained more violent 

 than usual. On examining the expectorated phlegm, which was tinged with 

 blood, it was fibrous, and when expanded in water, exactly resembling the 

 vessels in the lungs. These substances are as tough as the coats of the veins, 

 and like them hollow. The patient coughed up more or less of them every 

 day. for 7 years; sometimes perfectly white, and sometimes tinged with blood; 

 yet he has had no other complaint: has had a good appetite and colour, and a 

 greater share of fat than any man would choose. The specimen represented 

 fijr. 1, pi. 12, was expectorated when the Doctor was present, July 16, 1731. 

 It nearly resembles the first draft by Tulpius, and is no more than a viscid 

 phlegm, secreted by the relaxed glands of the trachea, and afterwards con- 

 creted by the heat of the part. 



An Experiment explaining a Mechanical Paradox, viz. that two Bodies of equal 

 JVeight suspended on a certain kind of Balance, do not lose their Equilibrium, 

 by being removed, the one farther from, the other nearer to the Centre. By 

 the Rev. T. J. Desaguliers, LL.D. et F.R.S. N" 419, p. 125. 



Prop. — If the two weights p, w, in fig. 2, pi, 12, hang at the ends of the 

 balance ab, whose centre of motion is c; those weights will act against each 

 other, because their directions are contrary, with forces made up of the quan- 

 tity of matter in each multiplied by its velocity; that is, by the velocity which 

 the motion of the balance turning about c will give to the body suspended. 

 Now the velocity of a heavy body is its perpendicular ascent or descent, as will 



