Temperature compensation means for refractometers

Claim 1

IN A REFRACTOMETER COMPRISING A MEASURING PRISM WITH AN ENTRANCE FACE FOR RECEIVING SUBSTANCES TO BE MEASURED, SAID SUBSTANCES HAVING INDICES OF REFRACTION DIFFERENT FROM ONE ANOTHER, A RETICLE, AN OPTICAL SYSTEM BETWEEN SAID ENTRANCE FACE AND SAID RETICLE FOR PROJECTING AN OPTICAL IMAGE OF LIGHT INCIDENT UPON SAID SYSTEM ONTO SAID RECTICLE, THE POSITION AND THE SIXE OF SAID OPTICAL IMAGE ON SAID RETICLE BEING A MEASURE OF THE REFRACTIVE INDICES OF SAID SUBSTANCES, SAID OPTICAL SYSTEM HAVING A MAGNIFICATION DETERMINING THE SIZE OF SAID OPTICAL IMAGE PROJECTED ONTO SAID RETICLE, AND COMPENSATING MEANS INCLUDING AN OBJECTIVE LENS AND TEMPERATURE-SENSITIVE MEANS FOR VARYING THE ANGULAR POSITION OF SAID OBJECTIVE LENS WITH RESPECT TO THE DIRECTION OF SAID INCIDENT LIGHT TO CHANGE SAID MAGNIFICATION AND TO CHANGE THE POSITION OF SAID IMAGE IN THE PLANE OF SAID RETICLE, BOTH AS A FUNCTION OF TEMPERATURE CHANGES, THEREBY COMPENSATING FOR THE CHANGES IN SAID REFRACTIVE INDICES WITH TEMPERATURE AND RENDERING SAID POSITION AND SAID SIZE OF SAID OPTICAL IMAGE IN THE PLANE OF SAID RETICLE SUBSTANTIALLY INDEPENDENTLY OF TEMPERATURE.