162 M E R 
no opportunit y of engaging them to publilh their works ; 
and to him the world is indebted for feveral important 
difcoveries, which would probably have been loft, but 
for his encouragement. No perfon could be more cu¬ 
rious than he was in penetrating into the fecrets of na¬ 
ture, and carrying all the arts and fciences to perfection. 
He was the chief friend and literary agent of Des Cartes 
at Paris ; giving him advice and affiftance upon all occa- 
iions, and informing him of all that palled in that city 
and ell'ewhere. So high was the opinion which Des Cartes 
formed of his knowledge and judgment, that he would 
fcarcely do any thing, or at leaft was not perfectly fatis- 
fied with any thing which he had done, without firft 
knowing what Merfenne thought of it. It is even faid, 
that, when Merfenne gave out at Paris that Des Cartes 
was ereCting a new fyllem of phyfics upon the founda¬ 
tion of a vacuum, and found the public indifferent to 
it on that very account, he immediately fent informa¬ 
tion to Des Cartes, that a vacuum was not the fafhion 
there ; upon which that philofopher changed his fyftem, 
and adopted the old doCtrine of a plenum. 
Merfenne alfo pofTeft'ed a good invention himfelf, and 
had a peculiar talent in forming curious queftions, though 
he did not always fucceed in refolving them ; however, 
he at leaft gave occafion to others to exercife their inge¬ 
nuity for that purpofe. It has been faid, that to him is 
to be afcribed the invention of the curve called the 
cycloid ; which was no fooner made public than it en¬ 
gaged the attention of the greateft geometricians of the 
age, among whom Merfenne himfelf held a diftinguifhed 
rank. Schooten, in his commentary on Des Cartes, fays, 
that the firft notion of this elegant curve was conceived 
by that philofopher, and that after him it was firft pub- 
lillied by father Merfenne in the year-1615. But Tor¬ 
ricelli affirms that this curve was confidered and named a 
cycloid by his predeceffors, and particularly by Galileo, 
about the year 1599 : and Dr. Wallis ffiows that it is of a 
much older Handing, having been known to Bovilli about 
the year 1500, and even confidered by cardinal Cufa be¬ 
fore the year 1451. 
Merfenne died in the year 1648. His lofs was deeply 
regretted by perlons of all ranks who were acquainted 
with him, by whom he was as much beloved for the 
cheerful qualities of his heart, and his mild and amiable 
temper, as he was refpe6ted for his profound fcientific 
knowledge. 
The firft work of any magnitude which father Mer¬ 
fenne publifhed, made its appearance in the year 1613, 
and is entitled, “ Quaeftiones celeberrimas in Genefim, 
cum accurata Textus Explicatione. In hoc Volumine 
,Athei et Deiftas impugnantur et expugnantur, &c.” folio. 
In that work he has entered into a particular refutation 
of the opinions of Vanini; and, as it was originally print¬ 
ed, it contained a lift of the other atheifts of his time, 
and their works. This part, however, his friends pre¬ 
vailed upon him to fupprefs, thinking it probably im¬ 
prudent, or dangerous, or that he had exaggerated their 
number beyond the limits of credibility. Accordingly, 
two leaves, containing columns 669 to 676, inclufive, 
were cancelled, and others fubftituted in their place ; as 
may yet be feen by a comparifon of the index under the 
word Athei, wdth that part of the work. There are 
copies in exiftence, however, in which the original leaves 
are to be found, though they are exceedingly rare. The 
chief of his other works are—2. Obfervationes et Emen- 
dationes ad Francifci Georgii Veneti Problemata in Ge¬ 
nefim, See. folio. 3. The Impiety of the Deifts, Atheifts, 
and moft fubtile Libertines of the Times, combated and 
completely refuted, by Reafons drawn from Philofophy 
and Divinity, 2 vols. 4. Univerfal Harmony, or the 
Theory and Practice of Mulic, &c. 2 vols. folio, 1636, 7. 
taken from a Latin edition, entitled Harmonicofium Li- 
Jjri XII. of which a corrected and enlarged impreffion 
nude its appearance in 1648, in folio, under the following 
M E R 
title : “ De Sonorum Natura, Caufis, et Efteftibus.” y. 
Univerfas Geometrias mixtaeque Mathematics Synopfis, 
et bini Refradtionum demonftratarum tradlatus, See. 
1644, 2 vols. 4to. 6. Cogitata phyfico-mathematica, See. 
2 vols. 4to. 7. On the Truth of the Sciences, in refutation 
of the opinions of fceptics or pyrrhonifts. 8. Qyeftims 
inouies, or Unheard-of Queftions, 4to. 9. Harmonical 
Queftions. 10. Theological, moral, phyfical, and ma¬ 
thematical, Queftions, &c. Sec. 
In the mufical writings of this diligent and ingenious 
ecclefiaftic may be found the moft minute and latisfadlory 
account of the ftate of mulic in France during the reign 
of Louis XIII. particularly in his Harmonie Univerfelte, a 
work in wffiich, through ail the partiality to his country, 
together wdth w'ant of tafte and method, there are fo many 
curious refearches and ingenious and philofophical expe¬ 
riments, w'hich have been of the greateft ufe to fubfequent 
writers, particularly Kircher, as render the book extremely' 
valuable. 
In his twenty-third propofition, book i. this author 
explains and deferibes twelve different kinds of mufic 
and movement, ufed in France during his time : thefe 
were motets, longs or airs, palfacailles, pavans, alle- 
mandes, gaillards, voltes, courantes, farabandes, cana¬ 
ries, branles, and balets ; of all which he gives exam¬ 
ples in notes. But, though moft of thefe movements 
were the fpecific names of the dances then in vogue, the 
minuet, which during the laft century was in Inch general 
favour all over Europe, is never mentioned. In other 
parts of his work he explains clearly the twelve keys 
major of practical mufic ; and fhows, for the firft time 
perhaps, that there may be feventy-two keys, or fix for 
each note, flat, natural, and fharp, major and minor. 
There is nothing which refledts more honour on his 
tafte and penetration than his partiality for the violin, 
to which he gives the preference over all other inftru- 
ments then in ufe, at a time when it was thought un¬ 
worthy of being admitted into the concerts of other 
countries. 
In book xxxiv. he inquires whether the French me¬ 
thod of finging is the bell of all poffible methods ? and 
determines in the affirmative, adding, that of all thofe 
he had heard fing in neighbouring countries, as in Spain, 
Germany, Flanders, and Italy, he had met with none 
who fung fo agreeably as the French. “ There may,” 
fays he, “ be now and then a miraculous performer in 
other countries 5 but I fpeak here in general.” He men¬ 
tions recitative as a thing little pradtifed in France. 
The Italians, he obferves, had fucceeded in this fpecies of 
finging, which Giacomo Peri had invented at Florence 
the beginning of the century. Here he fpcaks of feveral 
mufical draryas in Italy, but does not call them operas. 
The fi, to exprefs the feventh of the key, does not feem 
to have been in ufe at this time in France ; as Merfenne 
in his folmifation has never introduced it, repeating the 
mi, in the key of C, for E and B. Burney's Hijt. Mufic. 
MER'SEY, a river of England, which rifes in the 
county of Derby, then runs through the counties of 
Lancafter, York, and Chefter, and empties itfelf into the 
Jrifh Sea at Liverpool. Its whole extent is about fifty 
miles ; thirty-five of which are navigable, from Liverpool 
to the mouth of the river Irwell, for veilels of confider- 
able burthen. Oppolite Warrington in Lancaffiire, where 
it meets the tide-water, it is only forty yards wide; but 
at Runcorn-gap, where it communicates with the grand- 
trunk and duke of Bridgewater’s canals, its width is three 
hundred yards: below the gap, it extends itfelf into a 
grand eftuary of three miles in width, and receives the 
navigable river Weever from Northwich and Frodffiam. 
In its courfe northward from Runcorn, it gradually di- 
minilhes for fix miles, and oppolite Liverpool is only 
three-quarters of a mile wfide; but it forms a fine chan¬ 
nel, at leaft ten fathoms deep at low water, and is very 
commodious for flipping. About five miles farther, mea- 
3 luring 
