214 PROFESSOR T, ANDERSON ON THE PRODUCTS OF THE 



original pyridine ; but, unfortunately, there is no means by which its molecular 

 constitution can be determined. It is impossible to determine its vapour density, 

 because it undergoes partial decomposition at its boiling point ; and as its salts 

 do not crystallise, and probably, like the platinum compound, all correspond with 

 those of the original pyridine, there is no prospect of satisfactory conclusions 

 being drawn from them. In the absence of experimental evidence, any assump- 

 tion may be made regarding the constitution of this base, and at first sight the 

 most reasonable view of the matter is to suppose it to be the product of a further 

 polymerisation, and to be formed by the combination of three or four molecules of 

 the original pyridine. Its boiling point, which is certainly lower than that of 

 dipyridine, however, appears to militate against this view ; and taking its proper- 

 ties and those of its compounds into consideration, I am inclined to believe it to 

 be another dipyridine, and an example of those cases of physical isomerism of 

 which so many are now known. As there was no means of ascertaining the 

 constitution of this base, and the properties of its compounds were not encourag- 

 ing, I have not pursued their investigation further. 



Light Bases. 



It has been stated at the commencement of this paper that when dipyridine 

 was prepared by the first of the processes there described, that a light basic 

 oil was obtained at the beginning of the rectification of the crude product. This 

 oil, which is insoluble in water, was collected, dried, and rectified when it was 

 found to consist of several bases. The distillate was collected in several frac- 

 tions, which were analysed, but the quantity was far too small to admit of any 

 systematic attempt to separate them. The results, both of the combustion of the 

 bases themselves and of the platinum determinations in their platinum com- 

 pounds, seem to show that they are a class of bases isologous with the pyri- 

 dine series. I give here the results of these analyses : — 



{03025 gramme of base boiling between 225° and 240° F. gave 

 08375 ... ... carbonic acid, and 

 0-2302 water. 



i 0-4120 gramme of base boiling between 270° and 290° F. gave 

 1*1385 ... ... carbonic acid, and 



0-3230 ... ... water. 



f 0-2711 gramme of base boiling about 291° F. gave 

 0*7572 ... ... carbonic acid, and 

 01984 water. 



{0-2708 gramme of base boiling between 287° and 291° F. gave 

 0-7371 ... ... carbonic acid, and 

 0-2092 water. 



{0-2355 gramme of base boiling between 291° and 360° F. gave 

 06690 ... ... carbonic acid, 

 01795 water. 



