INTRODUCTORY NOTE. 



The following paper, prepared by the lamented William C. Eedfield expressly for this report, 

 may he looked upon as the very last offering to practical science of that eminent man, it having 

 been finished but a few days prior to the illness which terminated his life. 



It was my good fortune to enjoy for many years the friendly acquaintance of one, as remark- 

 able for modesty and unassuming pretensions, as for laborious observation and inquiry after 

 knowledge. 



To him, and to General Keid, of the Eoyal Engineers of England, are navigators mainly 

 indebted for the discovery of a law which has already contributed, and will continue to contribute, 

 greatly to the safety of vessels traversing the ocean. 



It is true, that subsequent writers, Piddington, Thorn, Fryers, Sedgewick and Bosquett, as 

 mentioned in the 1st volume of this work, have furnished additional information upon the subject, 

 but to Eedfield and Eeid should be ascribed the credit of the original discovery of this undeniable 

 law of nature, and its application to useful purposes ; and there can be nothing more beautiful, 

 as illustrative of the characters of these two men, than the fact, well known to myself, that, not- 

 withstanding their simultaneous observations and discoveries in distant parts of the world, 

 neither claimed the slightest merit over the other, but each strove to give to his co-worker in 

 research the meed of superior success in the great object of their joint labors ; and thus, without 

 ever meeting, a strong friendship was formed between them, growing out of congenial aspira- 

 tions for honorable fame, and mutual admiration of the generous and enlightened views exhibited 

 by each other ; and this enobling feeling was kept alive to the last by friendly correspondence.* 



I recollect, when sent abroad by the government, in 1838, to visit the dock-yards and light- 

 houses of England and France, I was favored with a letter of introduction from Mr. Eedfield to 

 his friend, then Colonel Eeid,t and I could well judge, by the many attentions and valuable 

 services rendered to me by that distinguished officer, and his verbal enquiries, how highly he 

 valued the recommendation of a man whom he had never seen.' 



M. C. PEEEY. 



<* The last letters of General Eeid arrived too late to be opened and read by the deceased, 

 f Now General Reid, and Governor of Malta. 



