I just emailed the pdf to my Kindle DX. The images are perfect, but the text is very small in portrait mode. As far as I can tell, I can't zoom or enlarge the t

I just emailed the pdf to my Kindle DX. The images are perfect, but the text is very small in portrait mode. As far as I can tell, I can't zoom or enlarge the text. The text becomes much more readable in landscape mode, but the reading columns are split between pages, so I have to go back and forth to read one complete page.