data1<-read.table("http://web.mst.edu/~wenx/teaching/stat6554/data/data-ex1304.txt",header=T)
 y<-data1$Acid
 trt<-data1$Method
 ftrt<-factor(trt)
 l1<-lm(y~ftrt)
 summary(l1)
 anova(l1)



 contrast.matrix<-rbind(
"contr 1"=c(2, -1,-1),
"contr 2"=c(0, 1, -1))

 
library(multcomp)
aov.trt<-aov(y~ftrt)
summary(glht(aov.trt,linfct=mcp(ftrt=contrast.matrix),alternative="two.sided"), test=adjusted("none"))




c1<-rep(contrast.matrix[1,],each=7)
c2<-rep(contrast.matrix[2,],each=7)

 anova(lm(y~c1+c2))
Analysis of Variance Table

Response: y
          Df Sum Sq Mean Sq F value    Pr(>F)    
c1         1 85.058  85.058  27.854  5.11e-05 ***
c2         1 62.287  62.287  20.397 0.0002672 ***
Residuals 18 54.967   3.054                      
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1