sew. i] DISSERTATION SECOND. 29 



paralleled in science, where a succession of able men, with- 

 out going wrong, advanced, nevertheless, so slowly in the 

 discovery of a truth which, when known, does not seem to 

 be of a very hidden and abstruse nature. Their slow pro' 

 gress arose from this, that they worked with an instrument, 

 the use of which they did not fully comprehend, and em- 

 ployed a language which expressed more than they were 

 prepared to understand ; — a language which, under the no- 

 tion, first of negative and then of imaginary quantities, seem- 

 ed to involve such mysteries as the accuracy of mathemati- 

 cal science must necessarily refuse to admit. 



The distinguished author of whom I have just been 

 speaking was born at Oxford in 1560. He was employed 

 in the second expedition sent out by Sir Walter Raleigh, to 

 ,. Virginia, and on his return published an account of that 

 country. He afterwards devoted himself entirely to the 

 study of the mathematicks ; and it appears from some of 

 his manuscript^ lately discovered, that he observed the 

 spots of the sun as early as December 1610, not more than 

 a month later than Galileo. He also made observations 

 on Jupiter's satellites, and on the comets of 1607, and of 

 1618. 1 



The succession of discoveries, above related, brought 

 the algebraick analysis, abstractly considered, into a state 

 of perfection, little short of that which it has attained at 

 the present moment. It was thus prepared for the step 

 which was about to be taken by Descartes, and which forms 

 one of the most important epochas in the history of the 



1 The manuscripts which contain these observations, and pro- 

 bably many other things of s;reat interest, are preserved in the 

 collection of the Earl of Esjremont, ha\ in«; come into the posses- 

 sion of his family from Henry Percy, Enrl of Northumberland, a 

 most liberal patron of science, with whom Harriot appears to 

 have chiefly lived after his return from Virginia. 



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