PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 711 



New Boilee. 



Mr. J. Wyatt Reid explaincu, with the aid of diagrams on the 

 blackboard, his new upright boiler. He increased the heating 

 surface by means of side pipes or flues, through which the smoke 

 ascended. 



Mr. W. Lee thought it would be more efficient with shorter 

 tubes. 



Mr. Joseph E. Miller remarked that there was more danger of 

 the crown sheet beino- overheated in this arrangement 



CpEjncAL Analysis by the Spectru^i. 



Dr. Vanderwej'^de exhibited a spectroscope and explained its 

 use. It is well known, he said, that flames of various colors are 

 produced by metallic compounds. When these flames are burned 

 before a narrow aperture, and the ray of light passing through it 

 is decomposed by a prism, spectra are produced which exhibit 

 different colored bands of light. When spectra of metals are ex- 

 amined, it is found that their flames give colors peculiar to each 

 metal. If five or six salts are mixed together and put into a tlame, 

 the presence of the minutest quantity of each can be recognized. 

 By ordinary chemical processes, it would require several hours 

 hard work to detect the presence of these bodies, but with the aid 

 of the spectrum this result may be arrived at in half a minute. 

 Caesium, a new metal, was discovered in a mineral water, where 

 it existed in so small a quantity that several tons were evaporated 

 to obtain one hundred grains of the metal. The constitution of 

 the sun's atmosphere has been found out, partially, by this method, 

 and it is impossible to foresee to what extent it may be used. 



Dr. L. Bradley read the following paper on 



COSMOGOXY. 



The hypothesis of Laplace assumes that the solar system was 

 once a nebula. How was it brought into this state ? 



By the patient and i::defatigable researches of Herschell, Struve, 

 Peters, Maedler and others, we are invested with the' knowledge 

 that the sun, in company with the innumerable other masses of 

 Idle milky way, are all in motion, and that they are all moving in 

 nearly the same direction. 



Combining the profound researches of Argelander, Struve and 

 Peters, we are now able to pronounce the following wonderful 

 results : 



