.. is about 50 minutes. i want to start by thanking the library of congress. it really is an exceptional library in the world. access to all people, whatever their nationality, free, at no charge, extended hours in the evenings and on saturdays. even formally sunday afternoons so perfect for people who are working at other jobs. it provides shelves for researchers, study desks. and no charge for reproducing images. this is really quite amazing and this is true for everyone so thank you to the library of congress. now, for my particular work the library has also been exceptionally helpful because there are very few libraries in the united states whose collections go back as far as the first half of the century. if you used the national union catalog and looking for books on sciences coming out of the europe and britain, you see dlc which is the abbreviation for the library of congress. the holdings are here and they re access enjoyable all. accessible to all. another rea