TIIK S'l'IUIiriUKIO OF TITK NTJCLKIIrt. 



77 



of discuutinuity, the coronas Hoen in the lioiizou are sciiucirculai', and not distorted 

 as above. This is often the case with carbon disulpliide. 



PRELIMINARY EXPERIMENTS WITH NUCLEI IN HYDROCARBON ANIJ OTHER VAPORS. 



The following experiments contain a cursory view of a luuuber of occurrences 

 which may be observed iu working with vapoi-s of the kind specified. Attention 

 will be directed to the coronal cok)i's and shapes, to the axial colors, to the spon- 

 taneous generation of nuclei in the dark, to the nuclei [)roducil)le by shaking licpiids 

 and solutions, to the velocity of these and other nuclei, etc. The more interesting 

 features will be reserved for quantitative determination in the subsequent chapters. 

 The apparatus is shown in Chapter III, figure 2, and will need no special descrip- 

 tion. During uucleation the filter,/, is replaced by an ionizer. 



10. Gasolene. Coronas and axial colors. — To test the se(|uence to axial 

 colors for this vapor, the drum was carefully dried and the successive exhaustions 

 made in the usual way. The results, tliough sliowing great intensity and abun- 

 dance of axial color, were so irregular as to the coronas that no systematic conclu- 

 sions could be drawn. Iloiizontal bands, dense or in colored strata, appeared in 

 place of the coi'onas. A copious gasolene rain was observed on the day following 

 tlie uucleation, together with small coronas. The difficulty, therefore, is absence of 

 homogeneity, and tlie endeavor to improve the conditions by rocking the drum 

 violently between the exhaustions proved of no avail. Energetic shaking of the 

 liquid within the drum alone evokes annular coronas, but this is a serious interfer- 

 ence with the experiment. The following table is an example of the results 

 reached t^ 



TABLE 2— BEHAVIOR OF SULPHUR NUCLEI IN GASOLENE VAPOR. 

 DRUM. EXHAUSTION, 76-68 cm. 



• Bl, blue ; op, opaque ; rd, red ; gr, green ; or, orange ; prp, purple ; viol, violet. 



