histogram cells

Why does the following code generate a Histogram of 7 cells
instead of 5?

Thanks for your help.
--Tommy

data(islands)
str(hist(sqrt(islands), br = 5, col="lightblue", border="pink"))

List of 7
 $ breaks     : num [1:8] 0 20 40 60 80 100 120 140
 $ counts     : int [1:7] 40 1 1 2 2 1 1
 $ intensities: num [1:7] 0.04167 0.00104 0.00104 0.00208 0.00208 ...
 $ density    : num [1:7] 0.04167 0.00104 0.00104 0.00208 0.00208 ...
 $ mids       : num [1:7] 10 30 50 70 90 110 130
 $ xname      : chr "sqrt(islands)"
 $ equidist   : logi TRUE
 - attr(*, "class")= chr "histogram"


--
Tommy E. Cathey, Senior Scientific Application Consultant
High Performance Computing & Scientific Visualization
SAIC, Supporting the EPA
Research Triangle Park, NC
919-541-1500 EMail: cathey.tommy at epa.gov
My e-mail does not reflect the opinion of SAIC or the EPA.

Federal Contact - John B. Smith
919-541-1087    - smith.johnb at epa.gov