1C6 Description of a mechanical Instrument to work 



right across the centre, and that called L,a Silla has sunk 

 more than sixty fathoms. 



It is difficult to say what will be the close of this dread- 

 ful event : it may be hazarded as a conjecture, however, 

 that it will end in the opening up of one or more volca- 

 noes : in the mean time the unfortunate inhabitants of 

 these countries, attached to their native soil, and not 

 wishing to abandon the ashes of their fathers, have with 

 great labour erected rude habitations, in which they await 

 with stoicism and resignation the termination of their car 

 lamities. j pj q 



XXVI. Description of a mechanical Instrument to work 

 Addition of Numbers luitli Accuracy and Dispatch. By. 

 Mr. J. Goss, oj Enjidd*. 



Sir, — About two years ago I resided at Hatherleigh in 

 Devonshire, v\here I had a day-school, and lodged with 

 people who kept a shop: they had frequent occasion to cast 

 up bills, but having but little knowledge of figures were 

 very liable to make mistakes ; they therefore, when a bill was 

 any way loner, generally brought it to me, and oftentimes, 

 when I have been out in the town, I have been sent for to 

 come home and cast up a bill ; at length I thought if some 

 mechanical contrivance could be invented to cast up bills, 

 it would be of great service to many, or even to all who are 

 in business. I knew that multiplication, division, and 

 many other rules in arithmetic, were often worked mechani- 

 cally; but addition being in itself so irregular, I was afraid 

 no instrument could be invented to work it. However, by 

 repeatedly considering the subject, I discovered after some 

 time a method of casting up a bill by a slide rule about two 

 feet long and two inches broad ; and as I was studying to 

 bring it to greater perfection, an imperfect idea of this 

 addition-wheel sprung up in my mind, which is a much 

 better method than the former : but thinking the experiment 

 would be attended with expense, and after all perhaps be of 

 no advantage ^o me, it lay dormant in my mind till about 

 last Michaelmas, at which time I came to London, and ^ 

 friend of mine got me one of the lists of premiums offered 



* ¥rom Tra?isaclions of the Societ;/ for Ihe Encouragement nf /fris. Manu- 

 factures, and Commerce, for 18l'L The silver medal of the Society was 



voted to Mr. Goss for this communication, and the Instrument is pre- 

 served in the Society's Repository. 



bv 



