NOTES BY THE EDITOR. VII 



cent chloride of aluminum to the salts used, and, by its antiseptic 

 qualities, afford a means of more thoroughly purifying thorough- 

 fares. 



Photography applied to military purposes is not new, but the 

 English government are making greater use of it than ever 

 before. 



Photographs are taken of soldiers exercised in the manual of 

 arms, both in the infantry and the artillery service; of the 

 lading of sumpter mules, and, in short, of everything which can 

 convey information to new recruits in the colonies. 



The preservation of meat has long attracted much attention 

 in this country and in Europe. The exportation of preserved 

 meats from Australia is becoming a business of great impor- 

 tance. Since the opening of the Pacific Railroad fruit and meat 

 have been transported to the Atlantic sea-board in closed refrig- 

 erator cars. In this connection it is well to notice the increased 

 use of artificial ice. The French company Messageries Impe- 

 riales, wishing to ascertain what kind of ice would be preferable 

 for the vessels navigating the Suez Canal, caused experiments 

 to be made under identical circumstances, and apparently proved 

 that artificial ice would have the preference over natural ice for 

 transportation, and for refrigerating mixtures. More experiments, 

 however, are needed to establish this fact. 



A paper on the continuity of the gaseous and liquid state of 

 matter, by Dr. Andrews, will be found on page 128 ; the transition 

 from the gaseous to the liquid state is shown not to be abrupt, but 

 that the two states are connected by a continuous change. The 

 writer infers, also, that liquids change to solids by a similar law. 

 The recent experiments made by M. Andre, on the velocity of 

 sound in water, give the velocity as 1206.5 metres per second. 

 Wertheim, it will be remembered, found it 1173 metres per second, 

 and MM.Colladon and Sturm, 1435 metres per second. Koenig's 

 investigation of the vowel sounds, supplementary to Helmholtz' 

 researches on the same subject, are interesting in a philological 

 point of view. He infers from the simplicity of the ratio of the 

 vibrations of the five vowel sounds found in all languages, the 

 reason of their universal adoption. 



M. Jamin has extended the use of electric currents to the 

 determination of latent heats and specific heats. In this con- 

 nection it is well to mention Siemens 1 resistance pyrometer. This 

 instrument will measure intense heat ; it is based upon the princi- 

 ple that metals offer a resistance to the passage of an electrical 



