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We have developed a computer program for the rapid assessment of the primary structure differences between a protein of unknown sequence and a homologous known protein. Both proteins are reduced, alkylated, and digested with the same hydrolytic agent. The unfractionated peptide mixtures are submitted to automatic sequence analysis. Based on the knowledge of the reference sequence, the program utilizes the analysis data to identify all the potential peptides present in the two mixtures, determining their primary structure, homology degree, and molecular weight calculated both as integer MH+ and average mass variables. These fingerprints allow the user to easily identify the structural differences between the two proteins and clarify possible doubts by a mass spectrometric analysis of the two mixtures. In order to verify the utility of the program, we provide an application example using the already reported data of two homologous proteins.

THE black mark earned by the government of the day more than a hundred years ago for its failure to see Charles Babbage's difference engine brought to a sucessful conclusion has still to be wiped out. It is not too much to say that it cost Britain the leading place in the art of mechanical computing. Babbage then conceived and worked on his ‘analytical engine’, designed to store numbers and operate on them according to a sequence of processes conveyed to the machine by cards similar to those used in the Jacquard loom. This, however, was never completed. A Manual of Operation for the Automatic Sequence Controlled Calculator By the Staff of the Computation Laboratory. (Annals of the Computation Laboratory of Harvard University, Vol. 1.) Pp. xiii + 561 + 17 plates. (Cambridge, Mass.: Harvard University Press; London: Oxford University Press, 1946.) 10 dollars.

A sequence generator for a polyphonic tone synthesizer in which a repetitive sequence of musical notes or chords are generated automatically. During a Code mode of operation, each key operated on the keyboard causes an associated data word identifying the specific key by keyboard, octave and note to be stored in a memory. Time data as to the relative time the note is to go on and go off is also stored as part of the data word. During a Play mode of operation, the data words are read out of memory in the sequence in which they were generated. The words are decoded and the time data compared with a real time clock to provide signals to the output of the keyboard which duplicate the signals from the corresponding keys. The time duration of these signals is controlled by the time on and time off data to duplicate the required time that the respective notes are to be played.

THE new I.B.M. Automatic Sequence Controlled Calculator at Harvard was recently described in Nature (158, 567; 1946). The volume now before us contains the first of a series of tables produced by the machine in its spare time ! Tables of the Modified Hankel Functions of Order One-Third and of their Derivatives By the Staff of the Computation Laboratory. (Annals of the Computation Laboratory of Harvard University, Vol. 2.) Pp. xxxvi + 235. (Cambridge, Mass.: Harvard University Press; London: Oxford University Press, 1945.) 10 dollars. 558.