Januaett 15, 1904.] 



SCIENCE. 



109 



double dating in -vogue during the time that 

 both church and civil almanacs were in use. 

 During this time a date falling betvreen Jan- 

 uary 1 and March 25 would by the church 

 almanac be a year earlier than the same date 

 on the civil almanac. This was sometimes 

 indicated by a double date thus, February 6, 

 1665/6. 



This was a point that I had overlooked, as 

 had also Drs. Eotch and Bolton. A reexamin- 

 ation of the various dates and of their con- 

 text leads to the following conclusions. John 

 Beale's letter was written February 6, 1665/6. 

 The paper cited by Dr. Eotch and myself is 

 of date March 24, 1665/6. Henry Oldenburg's 

 letter to Eobert Boyle, cited by me, is of date 

 March 19, 1665/6. 



During the year 1665 several instances of 

 the use of the word ' barometer ' are to be 

 found in Robert Boyle's correspondence. In 

 Robert Boyle's paper of April 2, 1666, he refers 

 to ' barometrical observations ' made by John 

 Beale; these observations Henry Oldenburg 

 transmits to Robert Boyle on December 19, 

 1665 (Vol. v., p. 343), and again on December 

 30, 1665, and on January 16, 1665/6. 



More interesting than the above is what 

 would seem to be the original passage in which 

 the word barometer is used. This passage I 

 found by following up the reference in John 

 Beale's letter to the three papers on 'thermom- 

 eters and baroscopes.' A close examination 

 of Robert Boyle's papers shows these to be 

 three papers printed with the ' History of 

 Cold ' in the spring of 1664/5. They are en- 

 titled ' New Thermometrical Experiments,' 

 and are preliminary to the ' History.' There 

 is also an introductory note by Henry Olden- 

 burg of date March 10, 1664/5, and beginning 

 thus : ' I am fully persuaded, you will much 

 rejoice to see that exquisite searcher of nature, 

 the illustrious Robert Boyle, come abroad 

 again, * * *' (Vol. II., p. 231). A little 

 further on he says : " I am now to advertise 

 you of one or two circumstances necessary to 

 be taken notice of in its perusal. One is 

 that the noble author being at Oxford, when 

 the book was printed at London, he hopes the 

 reader will not impute to him the errors of 

 the press, which yet he is persuaded will not 



be many, and out of which must be excepted 

 a blank or two, occasioned by this, that the 

 author's papers being near two years since 

 given to be transcribed to one. * * * " 

 This passage shows that the papers were writ- 

 ten by Robert Boyle prior to March, 1662/3. 



Turning to the author's preface we find the 

 following, " * * * how great a power my 

 friends have with me * * * the reader may 

 guess by the preamble he will find prefixed to 

 the first title of the ensuing history. For by 

 the date of that he will see how early my 

 papers about cold were to have been communi- 

 cated." The preamble bears date ' Little Chel- 

 sea, February 14, 1662, S. A.,' or 1663 civil 

 almanac. 



Turning to discourse I., we find the follow- 

 ing interesting passage: "Among the several 

 notes I find among my loose papers and in a 

 diary I kept for a while of these observations, 

 I shall content myself to transcribe the follow- 

 ing two. * * * The first of these memoran- 

 dums runs thus. Last night I took notice that 

 there was but one or two divisions difference 

 betwixt the two thermometers, but upon such 

 a change of weather, that happened this day, 

 as made me imagine that the atmosphere would 

 be lighter than before, consulting the barom- 

 eter (if to avoid circumlocutions, I may so 

 call the whole instrument wherein a mercurial 

 cylinder of 29 or 30 inches is kept suspended 

 after the manner of the Torricellian experi- 

 ment) * * *" (Vol. II., p. 244b). The 

 date of the diary from which these remarks 

 are taken is not given, and the best that can 

 be concluded from a reading of the whole 

 paper is to say that the date must be prior 

 to March, 1662/3, and probably prior to Feb- 

 ruary 14, 1662/3. Later on in the same paper 

 the word baroscope is used. 



It is a pity that Robert Boyle had not 

 earlier followed the determination of giving all 

 requisite dates, expressed by him in the fol- 

 lowing letter to Henry Oldenburg, dated Octo- 

 ber 26, 1667. " * * * Care will be taken for 

 the future, that the letters I send you be 

 dated. * * * And I am the more solicitous 

 about this matter, because frequent experi- 

 ence shews us how much our English have 

 lost, for want of being so; and (which is more 



