340 CONTRACTION OF WATER BY HEAT, 



tare it fhould contract, and in another expand, the very fame 



fubftance. Before a deviation from fo general a law (hould be 



.received as matter of lacl, the proofs of its exiftence ought to be 



. ckar and indisputable. 



been hitherto , The experiments hitherto publifhed, from which this fingula- 



exJerimentsTn &? lias ^ een Placed, have all of them been performed upon 



narrow nctked water contained in inftruments (haped like a thermometer glafs, 



veilels, anc j confiding of a ball with a flender ftem ; and the axpanfive 



or contractive effects of heat and cold have been inferred, from 



the afcent or defcent of the fluid in the ftem. 



of which tbe «- To fuch experiments it has been objected, that the dimenftons 



paaties alfo vary an( j ca p ac ity of the inftrument undergo fo much change, from 



temperature. variation of temperature, that it is difficult, if not impoffible, 



to determine how much of the apparent anomaly ought to be 



imputed to fuch changes, and that it is not improbable that the 



whole of it may be afcribed to them. 



The author The object of this paper, which I have now the honour 



jhows the effect {o rea( j to t h e f QC iety, is to prove by a fet of experiments, 



' conducted in a manner altogether different, that the common 



opinion is founded in Iritfh, and that water prefents itfelf as 



that ftrange and unaccountable anomaly which I have already 



defcribed. 



previous hiftory. It is worth while, before detailing my. experiments, to 



• . give a fliort account of thofe obfervations which led to the 



' difcovery of the fact, and wnich in fucceflion have extended 



our knowledge of it, as well as of thofe obfervations which 



. have at different periods been offered to difcredit, and to bring 



. it into doubt. 



Dr. Croune firft The fir ft obfervation relative to this fubject was made by 



obfervedthat D Croune, towards the clofe of the 17th century, while 



water appears to . ' J 



expand before it engaged in investigating tire phenomena ot the great and 



freezes. forcible, though familiar, expanfion which happens to water 



at the inftant of freezing; a matter which occupied in a 



confiderable degree, the attention of his fellow-members 



of the Royal Society of London in the earlier years of that 



inftitution. 



Hit narrative. I (hall relate in his own words his firft obfervation : " I filled 



The experiment a ft ron g bolt-head about half-way up the ftem with water, a day 



watertofe'in a or two before the great froft went off, marking the place where 



long necked tne vvater flood ; and placing it in the fnow on my leads, 



veOel by cool- wh ;j e j went to put f omei f a U to the fnow, I found it above 



