Nitro-aerial spirit

Mayow advances many speculations as to the functions of the nitro-aerial spirit, which show that he does not distinguish clearly between this spirit and the phenomena of heat generally, as in producing rigidity in bodies, and in affecting their elasticity, and that the elastic power of air is due to nitro-aerial spirit. He arrives at these conclusions on the basis of experiments described, but often misinterpreted. 

The similarity of respiration to ordinary combustion Mayow clearly comprehended. He cites the previous observation of Lower that the venous blood becomes bright red by the air in the lungs. Mayow cites experiments to show that blood which has been kept some time in a glass vessel and is bright red only at the surface, when placed under the air pump, will at the surface effervesce gently and rise in bubbles, but fresh arterial blood on the other hand will, in vacuo, expand remarkably and rise in an almost infinite number of bubbles. Mayow considers that the nitro aerial spirit thus absorbed in the lungs by the blood plays the same part as in other combustions and this accounts for the heat of the animal body. 

By the end of the talk, the room was so smoky that several ladies had to be escorted out. Wepfer said that there was time for only three questions. My hand shot up, and he turned to me with amusement. I wonder if you are familiar with John Mayow and his conclusions about fire and air I asked. His smile faded, but he nodded gravely. Then you ll know that Mayow noticed that if a mouse was placed under a glass, it could not live after part of the air—the part he called the nitro-aerial spirit—had been consumed, even though some air was left in the glass. Likewise with a candle flame. How does Mayow s theory that air in fact consists of at least two different parts fit your theory of the Archaeus, which you say is a force separate from the air ... 

GUN POWDER, LIGHTNING AND THUNDER, AND NITRO-AERIAL SPIRIT 217... 

FIGURE 150. This plate is from John Mayow s Tractus Quinque Medico Physici Ox-ford, 1674). It shows his experiments in which nitrO aerial spirit in saltpetre was trans ferred to antimony under a heating glass. In effect oxygen was transferred between the two substances (from the Dr. Roy G. Neville Historical Chemical Library, a collection in the Othmer Library, CHF). 

The Tractatus Quinque concerned itself with other scientific questions beyond the medical, physiological, and chemical. For example, Mayow discussed the origins of water spouts as due to air turbulence (see Figures 151 and 152 see also Benjamin Franklin s studies of these phenomena and Figure 119 later in this book). Mayow s explanation of lightning and thunder are reminiscent of those of Paracelsus and imagine explosions between nitro-aerial spirit and sulphureous matter in the atmosphere. 

W. Hewson, E eriments on the Blood, Phil. Trans., 1770, lx, 368-413 (373) repr. in lus Experimental Inquiries Part the First. Being a Second Edition of an Inquiry into the Properties of the Blood, 1772, 10 The Works of William Hewson, ed. G. Gulliver, 1846, 11 (the note says perhaps Mayow s nitro-aerial spirit may be here confounded with nitre ). 

---