Our learning how to write a *cantus firmus* taught us to distinguish between **conjunct** and **disjunct** motion, **consonant** and **dissonant** melodic intervals, the distinctions between steps, skips, small leaps (of a fourth), and large leaps of a fifth or more, also, the differences between several **modes**. 

We learned that, in a *cantus firmus*, certain **melodic** intervals are acceptable – major and minor seconds, thirds (also sixths), perfect fourths, also perfect fifths and octaves – whereas others are NOT: i.e., sevenths, also chromatic, diminished, augmented, and compound intervals. 

In order to combine together two independent melodic lines – a *cantus firmus* and a *counterpoint* – we begin with exercises in “species counterpoint.” This refers to the specific note values of the counterpoint – whether whole, half, or quarter notes – in relation to the CF. Yes, we’re talking about **rhythm**. 

When a **counterpoint [CP]** in whole notes is matched to an existing *cantus firmus* – also in whole notes, whether above or below, it is called **First Species Counterpoint**, or **“note against note.”** Listen to this [...]

VIDEO
https://youtu.be/dF5U6VS93ZA

LIBRARY REFERENCES, in Alphabetical Order
Fux, Johann Joseph, *Gradus ad Parnassum*. Reprint of original, in Latin. A Public Domain work (1725)
Link: http://imslp.org/wiki/Gradus_ad_Parnassum_(Fux,_Johann_Joseph)
Schubert, Peter. *Modal Counterpoint*.
Salzer, Felix, and Carl Schachter: *Counterpoint in Composition*. McGraw-Hill: New York, 1969.

IMAGES, from Flickr, in Order of Appearance
Relax, by Peter Samow (mods and commercial use allowed): https://flic.kr/p/fEzkyy
Halong Bay islands w/ sunset tint, by Neville Wootton (mods and commercial use allowed): https://flic.kr/p/ShVoJ5
Fish – “harmony,” by Ernesto Pletsch (mods and commercial use allowed): https://flic.kr/p/8ruCvv
Solar System Transits, by Giuseppe Donatiello: https://flic.kr/p/JXQovz

Creative Commons Legal Code for commercial use and mods of above images. “Mods” used (if any), are minor adjustments to image size, transparency, cropping, and/or front-to-back position in slide): https://creativecommons.org/licenses/by-sa/2.0/legalcode