library(ggplot2)
#library(reshape2)

df=read.csv("https://8n1.org/raw/24061/52c2")

head(df)

COP266=df[,1]
COP275=df[,2]
COP280=df[,3]
COP283=df[,4]


df266=data.frame(x=rep(266,length(COP266)),y=COP266)
df275=data.frame(x=rep(275,length(COP275)),y=COP275)
df280=data.frame(x=rep(280,length(COP280)),y=COP280)
df283=data.frame(x=rep(283,length(COP283)),y=COP283)

COPMAX=data.frame(x=0:300)
COPMAX$y=1.0*(308.15/(308.15-COPMAX$x))

COP60=data.frame(x=0:300)
COP60$y=0.6*(308.15/(308.15-COPMAX$x))

COP30=data.frame(x=0:300)
COP30$y=0.3*(308.15/(308.15-COPMAX$x))


ggplot() +
  geom_point(data=df266,aes(x=x,y=y))+
  geom_point(data=df275,aes(x=x,y=y))+
  geom_point(data=df280,aes(x=x,y=y))+
  geom_point(data=df283,aes(x=x,y=y))+
  geom_line(data=COPMAX,aes(x=x,y=y))+
#  geom_line(data=COP30,aes(x=x,y=y))+
#  geom_line(data=COP60,aes(x=x,y=y))+
  ylim(0,10)+
  scale_y_continuous(breaks = seq(1, 7, by = 0.5))+
  xlim(250,280)

# Save plot as PDF
ggsave("sample_plot.pdf", device = "pdf",width = 5, height = 4)