VOL. XXXIV.] VHILOSOPHICAL TRANSACTIONS. 103 



Two newly discovered Arteries, going to the Ovaria in IVomen. By Mr. Ranby, 

 Surgeon to his Majesty s Household. F.R.S. N°365, p. 159. 



In the Philos. Trans. N° 387, Mr. R. presented the Royal Society with a 

 description of two arteries, which arising from the aorta, and sending branches 

 to the glandula renalis, then descend to the testicles. And he has since found 

 the same arteries in women, descending in the same common capsula with the 

 spermatic artery and vein, to the ovaria. These arteries very probably are what 

 the late excellent anatomist, Valsalva, took for excretory ducts of the glandulas 

 renales, the disposition and progress of these being very much alike to what has 

 been ascribed to those supposed ducts. 



A short Account of Negativo-qffirmative Arithmetic. By Mr. John Colson, F.R.S. 

 N°396, p. 161. 



The usefulness of this arithmetic consists in this, that it performs all the 

 operations with more ease and expedition than the common affirmative arith- 

 metic, especially in large numbers : and it differs from the common arithmetic 

 chiefly in this, that it admits of negative figures promiscuously with the affirma- 

 tive. These negative figures are distinguished from the affirmative, by the 



sign - placed over them. Thus 3709286573961472 is one of these numbers, 

 which may be converted into its equivalent common number 2308726432039468, 

 in this manner : 



3009006503000470 



070028OO70961002 



23O8726432039468 

 1. Write down all the affirmative figures by themselves, putting a cypher in 

 the place of every negative figure. 2. Write down all the negative fi.gures by 

 themselves, putting a cypher in the place of every affirmative figure. 3. Sub- 

 tract the last number from the first, and the remainder will be a common num- 

 ber, equivalent to the given negativo-affirmative number. See the operation 

 above. 



But the readiest practical way of performing this reduction in any given num- 

 ber, is in this manner: begin at the left hand; and going over all the figures 

 in order, observe these rules. 1 . An affirmative figure before a negative must 

 be diminished by a unit, 2. A negative figure before an affirmative, must be 

 changed into its complement to 10. 3. A negative figure before a negative, 

 must be changed into its complement to 9. All other figures must remain un- 



Y 2 



