tell application "Mail"
    set outgoingMessage to make new outgoing message
    set fontFace to "Times"
    tell outgoingMessage
        set the content to " "
        set font of content to fontFace
        set size of content to (14)
        set visible to true
    end tell
end tell

try
    try
        set old to the clipboard
    end try
    set html to quoted form of "<span style="font:14px 'Monaco'">&nbsp;</span>"
    do shell script "echo " & html & " | textutil -format html -convert rtf -stdin -stdout | pbcopy -Prefer rtf"
    tell application "System Events" to keystroke "v" using command down
    delay 0.03
    set the clipboard to old
end try

try
    try
        set old to the clipboard
    end try
    tell application "System Events" to keystroke "c" using command down
    delay 0.03
    set input to Unicode text of (the clipboard as record)
    set txt to quoted form of ("<span style="font:14px 'Monaco'">" & input & "</span>")
    do shell script "echo " & txt & " | textutil -format html -convert rtf -stdin -stdout | pbcopy -Prefer rtf"
    tell application "System Events" to keystroke "v" using command down
    delay 0.03
    set the clipboard to old
end try