VOL. XXXVII.] PHILOSOPHICAL TRANSACTIONS. 447 



1. The bores that carry off the water from the forcers are too small, there 

 being nearly always 2 columns of 7 inches diameter, forcing into one pipe of 

 the same diameter, and 7 X 7 = 49 + 49 = 98. 



Therefore, those pipes of conveyance should be near 9 inches in diameter. 



The timber-work is all admirably well executed; and the composition and 

 contrivance, both for strength and usefulness, not exceeded by any he has seen. 



The cranks of cast-iron are better than of wrought iron; by reason they are 

 very stiff, and will not be strained, but sooner break; and then they are cheap, 

 and new ones easily put in. 



The wedge for putting on, or releasing the crank and forcers, is better than 

 the sliding sockets, commonly made use of. 



The forcing barrels, trunks, and all their apparatus, are very curiously con- 

 trived for putting together, mending, altering, or cleansing, and subject to as 

 little friction as possible in that part. 



The machine for raising and falling the wheels is very good, though but sel- 

 dom used, as he is informed: for, they will go at almost any depth of water, 

 and as the tide turns, the wheels go the same way with it. 



These machines at London-bridge are far superior to those so much famed at 

 Marley in France, as the latter are very ill contrived in the cranks, and some 

 other parts. 



Account of a Stone broken in the Bladder, and voided through the Urethra. By 

 Lawrence Heiste.r* M. D. N" 417, p. 13. An Abstract from the Latin. 



A man upwards of 60 years of age, of a robust constitution, and addicted to 

 free living, had for some years past been troubled with frequent and violent 



* Lawrence Heister was a native of Frankfort on tlie Mayne, and professor of anatomy and sur- 

 gery, first at Altdorf, and afterwards at Helmstadt. He studied under Ruysch, Bidloo, Albinus and 

 Boerhaave, and was surgeon to the Dutch forces during the campaigns of 1707 and 1709, when the 

 war in Flanders afforded him frequent opportunities of displaying his medical and chirurgical skill. 

 Besides a variety of smaller ti-acts, he wrote a very useful manual of anatomy, entitled " Compen- 

 dium Analomicum," 1717, 4to. which has been frequently reprinted, and has moreover been trans- 

 lated into most of the European languages; Compendium Institutionuni Medicinae, 4to. 1736; 

 Compendium Med. Practicee, 1 vols. 8vo. 17-13 ; Chirurgiae Institutiones, 4to. 174S, exhibiting an 

 excellent systematic view of surgery, drawn from the most approved authors, both ancient and 

 modern, and accompanied with numerous original observations and improvements. This work pro- 

 cured him a great reputation ; it has gone through many editions, and has been translated into 

 English, German, French, &c. After his death a collection of his medical, surgical, and anatomi- 

 cal observations, was published in 2 vols. 4to. 1753 — 1770, in the German language. Heister, as 

 his friend Haller has remarked, was a diligent and, industrious teacher, as well as an able and suc- 

 cessful practitioner. It was in anatomy and surgery that he chiefly excelled, the knowledge of which 

 he greatly promoted by his lectures, as well as by his writings. He was a good operator, and suggested 

 many improvements in tlie construction of surgical instruments. 



