||M1 limited industrial district. Intent. The regulations of this district are set up to provide land for various types of industrial and manufacturing uses that are compatible with one another. The lands included in this district are those suited for use primarily by industries characterized by low land coverage, the absence of objectionable external effects and the possibility of large setbacks, attractive building architecture and large, landscaped park-like areas. The purpose of the district is to provide suitable sites for such uses while making certain that such uses will be compatible with adjacent or surrounding districts. To these ends, development is limited to a low concentration, external effects are minimized and permitted uses are limited to those which are adapted to an environment of this nature. The regulations are also designed to stabilize and protect the essential characteristics of the district by excluding uses which would have a detrimental effect upon the orderly development and functioning of the district. Manufacturing plants and uses shall have performance characteristics similar to those uses listed in this district in that they emit a minimum of noise, vibration, smoke, dust, dirt, toxic or offensive odors or gases, glare, electromagnetic or atomic radiation. All uses located within this district shall be so designed, constructed and operated that there is no production of sound discernible at the lot lines in excess of the average intensity of street and traffic noise at the lines, nor any production of heat or glare discernible at the same point. (2) Permitted principal uses. Any principal use permitted in the RE research district or O office district (except residential uses). Special trade construction contractors; wholesale trade -- building materials and wholesalers. Transportation, communications, electric, gas and sanitary services. Laundry, cleaning and garment services. Industrial plants, manufacturing, processing or assembling the following: Agricultural products. Food and kindred products, excluding slaughterhouses. Furniture and fixtures. Converted paper and paperboard products. Printing, publishing and allied industries. Biological products, drugs, medicinal, chemical and pharmaceutical preparation. Glass products, made of purchased glass. Electrical and electronic machinery, equipment and supplies. Measuring, analyzing and controlling instruments; photographic, medical and optical goods; watches and clocks. Jewelry, silverware and plated ware; musical instruments; toys and amusement, sporting and athletic goods; pens, pencils and other office and artists' materials; costume jewelry, costume novelties, buttons and miscellaneous notions; and signs and advertising displays. Canvas products made of purchased canvas. Fabricated metal products, except heavy machinery and transportation equipment. Metalworking machinery and equipment; general industrial machinery and equipment. Office, computing and accounting machines. Jobbing and repair machine shops. Any other manufacturing plants and uses having performance characteristics similar to those listed in this district in that they emit a minimum of noise, vibration, smoke, dust, dirt, toxic or offensive odors or gases, glare, electromagnetic or atomic radiation and odor. All uses located within this district shall be so designed, constructed and operated that there is no production of sound discernible at the lot lines in excess of the average intensity of street and traffic noise at the lines, nor any production of heat or glare discernible at the same point. General repair of automobiles, trucks and construction equipment.