For 'gay', since there is no sense cluster in the older time period with 'gay' being a noun, cluster comparison does not even detect the 'birth' cluster of 'gay'. The 'birth' sense clusters for 'guy', 'bush' in the new time period, as detected by <cite>split-join algorithm</cite> contain general terms like "someone, anyone, men, woman, mother, son" and "cloud, air, sky, sunlight" respectively. As the network around these words did not change much over time, our method found it difficult to detect.