Newton's Letters to Oldenburg and Boyle. 185 



It is almost doubtful whether it be convenient or not to call 

 this sound an articulation. However, it enters into the con- 

 stitution of speech, and is expressed in English by the letter h. 



A sound equally simple may be formed by drawing in a 

 breath, when the sound is formed by a current of air passing 

 from the mouth to the lungs. This is the sound of k formed 

 by means of an inspiration. The existence of this sound in 

 speech is problematical. In some of the Hottentot languages 

 described as. containing, amongst their fundamental sounds, 

 inarticulate clicks and catches, it may possibly exist. 



By breathing an expiration through the nose instead of 

 through the mouth, we may form a nasal variation of h. 



By drawing a breath through the nose, instead of through 

 the mouth, we may form a nasal variation of the second 

 sound. 



Hence, of even the simplest breathing, there are four pos- 

 sible forms. 



I. Oral, where the breath passes through the mouth. 



a. The breath expired = h. 



b. The breath inspired. 



II. Nasal, where the current of breath passes through the 

 nose. 



a. The breath expired. 



b. The breath inspired. 



Of these four possible varieties of the simple breathing, it is 

 only the first that is known to be used in speech. The sounds 

 formed by mere breathings are of course both surd and con- 

 tinuous. The consideration of the sounds formed by passing 

 a current of air through the nostrils is important. 



The possible varieties of a simple current of unmodified 

 breath have thus been enumerated. The difference between 

 ^rpired and mspired forms is of little practical importance, 

 since the articulations of real language are, with a few pro- 

 blematical exceptions, all expired. On the other hand, the 

 difference between air erpired through the mouth and air ex- 

 pired through the nostrils, has (as will be shown in some 

 future communication) been much underrated. 



XXXV. Newton's Letters to Oldenburg and Boyle respecting 

 his Theory of Light and Colours. 



To Richard Taylor, Esq. 

 Dear Sir, 



T^HE letter to Oldenburg, of which I gave an account in 

 ■*- one of your former Numbers, as containing the first 

 draught of Newton's speculations respecting an oetherial 

 Phil. Mag. S. 3. Vol. 29. No. 193. Sept. 1 846. O 



