These ornaments should be played "with regard for their value and upon the beat";[192] however, an excessive rigor in this respect should not be affected; Bach did not exact such precision, and did not attach to these figures such great importance that he did not feel at liberty to substitute for them, in copies of these same pieces made by himself, other and practically equivalent ones. Certain of them are, moreover, quite rare; for example, the _accent_. We find it employed, at least in the organ compositions, only in an arrangement of the chorale _Allein Gott in der Höh' sei Ehr'_ (_Gloria in excelsis_). No piece could be more elaborated than this one; and in it are introduced a majority of the signs employed by Bach; we borrow from Mr. E. Dannreuther's interesting work, "Musical Ornamentation,"[193] the transcription of the first six measures of this chorale, fully written out. Such an example will be more instructive than all we could say upon this subject, if the reader will take pains to compare this interpretation with the musical text as found in the well-known editions:[194] [Music] [Footnote 192: L. Diémer: _Les Clavecinistes français du XVIIIe siècle_ (Durand and Schönewerk).] [Footnote 193: This work contains, with numerous examples, a study of ornamentation, from G. Diruta to J.S. Bach in the first part, from Ph. E. Bach to our own period in the second. (London: Novello, Ewer & Co.)] [Footnote 194: P. vi, 9. B.-G.] This is evidently a species of appoggiatura, as also in the chorale _Vater unser im Himmelreich_ (_Clavierübung_, Part III). But in this case, Bach uses a special notation: [Music] In his Method for clavecin Ph. E. Bach, in speaking of a similar figure, thus explains it: "The first note of this figure must not be made too short, if the tempo be slow or moderate; for the second would then be held too long. It should be gently dwelt upon, not suddenly hammered." "Play _flautato_," says W. Rust[195] upon the subject of such a fugue in an orchestral part; one should thus anticipate the beat with the flutist's stroke of the tongue, according to Quantz (_Essai d'une méthode pour apprendre à jouer de la Flûte traversière_. Berlin, 1752); that is to say, that the first of the two notes should be considered as written thus: [Music] [Footnote 195: B.-G. xiii, p. xvi. We again encounter this grouping in the flute part of the _et in unum Deum_ of the _B_ minor Mass.] In a solfeggio lesson by J.G. Walther,[196] written in 1708, this indication, called _punctus serpens_, signifies that the notes are to be slurred; that is, bound together, two by two. This is, undoubtedly, the most correct interpretation, which fairly corresponds to what S. Scheidt calls "_imitatio violistica_." [Footnote 196: The autograph was contained in the collection of Ph. Spitta.] Analogous notations of Frescobaldi[197] and Muffat[198] indicate a similar manner of execution. [Footnote 197: _Toccata_ II (_libro_ i).]